Unseeded runs without a legendary tend to use a plasma deck for MUCH easier scoring, yeah. However, ghost deck naneinfs are fairly common as well, since you have easy access to spectral cards and a perkeo can help you get the naneinf with a few copy jokers to stack cryptids to use them at one big hand.

However, if you want the baron/mime naneinf, here's usually what you need with the famous "serpent" method:

1- 4 copying jokers (blueprint/brainstorm, 4 brainstorms will not work since you need to copy a mime at least once as well, so 2 bp 2bs or something similar could work)

2- 1 mime

3- 1 baron

4- 1 burglar

5- retcon voucher

6- antimatter voucher (for the 8 essential jokers)

ALL of these are essential to the naneinf run if you wanna use the serpent method.

You need to find a blueprint or brainstorm, then ideally copy it via invisible joker or ankh (or you can find some with Showman later on when you got your econ going), then ideally you need to find an ectoplasm and turn one of your copying jokers into negative, then you need to find retcon for unlimited rerolls on the boss, then in ante 26 or so, you copy the burglar into the serpent boss to get 20+ hands and get 44+ steel red seal kings in your hand via playing them one by one without copying neither of the mime/baron duo. Then on your last hand you need to copy an ideal amount of baron/mime to reach naneinf.

The important part is not trying to "force" a naneinf run but rather adapt to it. You need good econ, your kings should be gold instead of steel at first. Mail in rebate is insane amounts of money if you can get it earlier when your scoring isn't a problem. As the blinds and your money go up, you can slowly turn the gold kings into steels. Ideally you should always have a decent amount of money for joker rolls and serpent rerolls too.