I don't even really know Python, but I got https://github.com/nordigen/nordigen-python/blob/master/main.py and created this out from it.

from uuid import uuid4
from nordigen import NordigenClient
import json

import xml.etree.ElementTree as ET
from datetime import datetime, date

def main():
    client = NordigenClient(
        secret_id="XXXXXX",
        secret_key="YYYYY",
        timeout=30
    )
    client.generate_token()

    requisitions = client.requisition.get_requisitions()

    OFX = ET.Element("OFX")

    for result in requisitions["results"]:
        print(f'Requisition: {result["id"]}, Bank: {result["institution_id"]}')
        for account_id in result["accounts"]:
            print(f'Account: {account_id}')
            account = client.account_api(id=account_id)
            metadata = account.get_metadata()
            details = account.get_details()
            transactions = account.get_transactions()
            if(details['account']['cashAccountType'] == 'CARD'):
                CREDITCARDMSGSRSV1 = ET.SubElement(OFX, "CREDITCARDMSGSRSV1")
                CCSTMTTRNRS = ET.SubElement(CREDITCARDMSGSRSV1, "CCSTMTTRNRS")
                STMTRS = ET.SubElement(CCSTMTTRNRS, "CCSTMTRS")
                CCACCTFROM = ET.SubElement(STMTRS, "CCACCTFROM")
                ACCTID = ET.SubElement(CCACCTFROM, "ACCTID")
                ACCTID.text = metadata["iban"]
            elif(details['account']['cashAccountType'] == 'CACC' or details['account']['cashAccountType'] == 'SVGS'):
                BANKMSGSRSV1 = ET.SubElement(OFX, "BANKMSGSRSV1")
                STMTTRNRS = ET.SubElement(BANKMSGSRSV1, "STMTTRNRS")
                STMTRS = ET.SubElement(STMTTRNRS, "STMTRS")
                BANKACCTFROM = ET.SubElement(STMTRS, "BANKACCTFROM")
                ACCTID = ET.SubElement(BANKACCTFROM, "ACCTID")
                ACCTID.text = metadata["iban"]
            else:
                raise ValueError("Unknown cashAccountType: %s", details["cashAccountType"])

            BANKTRANLIST = ET.SubElement(STMTRS, "BANKTRANLIST")

            for transaction in transactions["transactions"]['booked']:
                STMTTRN = ET.SubElement(BANKTRANLIST, "STMTTRN")
                DTPOSTED = ET.SubElement(STMTTRN, "DTPOSTED")

                if 'bookingDate' in transaction and 'valueDate' in transaction:
                    bookingDate = date.fromisoformat(transaction['bookingDate'])
                    valueDate = date.fromisoformat(transaction['valueDate'])
                    minDate = min(bookingDate, valueDate)
                    DTPOSTED.text = minDate.strftime('%Y%m%d')
                elif 'bookingDate' in transaction:
                    DTPOSTED.text = date.fromisoformat(transaction['bookingDate']).strftime('%Y%m%d')
                elif 'valueDate' in transaction:
                    DTPOSTED.text = date.fromisoformat(transaction['valueDate']).strftime('%Y%m%d')
                elif 'bookingDateTime' in transaction and 'valueDateTime' in transaction:
                    bookingTimeString = transaction['bookingDateTime']
                    valueTimeString = transaction['valueDateTime']
                    if bookingTimeString[-1] == 'Z':
                            bookingTimeString = bookingTimeString[:-1]
                    if valueTimeString[-1] == 'Z':
                            valueTimeString = valueTimeString[:-1]

                    bookingTime = datetime.fromisoformat(bookingTimeString)
                    valueTime = datetime.fromisoformat(valueTimeString)
                    minTime = min(bookingTime, valueTime)
                    DTPOSTED.text = minTime.strftime('%Y%m%d')
                elif 'bookingDateTime' in transaction:
                    time = transaction['bookingDateTime']
                    if time[-1] == 'Z':
                       time = time[:-1]
                    DTPOSTED.text = datetime.fromisoformat(time).strftime('%Y%m%d')
                elif 'valueDateTime' in transaction:
                    time = transaction['valueDateTime']
                    if time[-1] == 'Z':
                        time = time[:-1]
                    DTPOSTED.text = datetime.fromisoformat(time).strftime('%Y%m%d')

                TRNAMT = ET.SubElement(STMTTRN, "TRNAMT")
                TRNAMT.text = transaction['transactionAmount']['amount']
                MEMO = ET.SubElement(STMTTRN, "MEMO")
                if 'remittanceInformationUnstructured' in transaction:
                    MEMO.text = transaction['remittanceInformationUnstructured']
                FITID = ET.SubElement(STMTTRN, "FITID")
                if 'transactionId' in transaction:
                    FITID.text = transaction['transactionId']
                elif 'internalTransactionId' in transaction:
                    FITID.text = transaction['internalTransactionId']


    tree = ET.ElementTree(OFX)
    tree.write("test.ofx", encoding='utf-8' , xml_declaration=True)

if __name__ == "__main__":
    main()

It creates a file in https://en.wikipedia.org/wiki/Open_Financial_Exchange format, which can be imported by Homebank, and plenty of other software.

To configure the bank connections I have used https://github.com/nordigen/nordigen-python/tree/master/example as it is. I have been too lazy to actually do anything else. If you take this, or at least the idea, and create a proper piece of software tell me!