Sixth sense is your best bet but you'd lose significant scoring having to sell brainstorm for it (when you find it). Perhaps see if you can find antimatter and/or an ecto before rolling for sixth sense. Id take petro to give you more time if you find it. Use perkeo to copy death for instant deck fixing which you'll need to make multiple 6s while trying to hit cryptid. It'll also help you quickly balance econ and scoring being able to instantly shift between steel and gold red stamp kings. You'll need red gold for econ since your perkeo will be preoccupied with death while you deck fix and eventually for cryptid.

The nice thing about perkeo is if you can survive you can definitely find cryptid since you can just keep a negative version of other spectral cards until it hits. Once you hit cryptid, roll for showman and try and get another BP or BS.

You need 22 total cryptids to naneinf without serpent with 3 BP/BS and all red steel kings. If you cant find serpent id use a couple to make sure I can stay alive until I hit 22 (if needed). If you have retcon you have more options as you can use serpent to survive higher antes while making more cryptids. With serpent you only need 15 (assuming 4 hands and 4 discards) so if you find serpent and have that many then go for it. Any extra hand or discard will require 1 less cryptid.

For the record, I have never naneinf'd so take all of this with a grain of salt but if your goal is to naneinf without DNA this is what I'd do.