Alot of the time, no matter what is going on,... change of food, cleaning cage, or just trying to get him to step up,... he chews his feet and bites his toenails like he hasn't eaten in weeks!! Is this normal?

sorry I can't help much but my qp chews her feet when she is preening. It might jst be that.
I'm sure people who know more will come by soon

my quaker chews her feet and she's been doing this since i got my cockatiel last year. i took her to the vet recently and she told me that she was doing this due to anxiety possibly because of the new bird. her suggestions were to keep new toys and rotating things around in the cage to keep her occupied because unfortunately once they get started on something it becomes obsessive. i hope this helps!

Pico will bite one leg. Or pretends too-- also. I think he does this if I'm ignoring him or if he dosn't like something.I just get his attention unto something else or sing to him and he will stop.

Clyde bites his nails, too, when he's preening. In vain I have tried to explain to him that this is an unattractive habit. Unless yours injures himself, maybe you could just try to distract him by getting him to talk or whistling at him or something?

As others have already said its pretty common however...if it is causing damage to his legs a trip to the vet is in order.