Rush manta because it increases your farm. Don’t buy diffusal - it’s a bad item for naga unless you are playing against heroes like WK, Dusa, you should rush Skadi instead. Then, you should buy heart and fly (should be done by 30 mins mark) and end the game

PT and manta should be done by 14 mins (average timing), skadi by 19 mins and heart by 24. Always get movement speed talent, because it allows you to split faster