I don't get it, new MOSFET and a new ATMEGA and all is well. No idea. If anyone needs parts I have a set of everything needed from mouser and digikey except for the probes, PCB, mosfet, case, and atmega I'll sell at a discount over what I paid, heh.
I will, in the appropriate section. Seems to work great, I'm using thermoworks probes and they seem to be doing great, I'm going to build a UDS to tinker with and play with the PID settings. It's a really slick little device and despite the weird problems I had has been a fun project.
the MOSFET I got from digikey is a lot smaller than the one from mouser, maybe I had the wrong one, who knows.