Nothing is the answer to both.
None and nothing depends on the sentence, but in general, "none" goes with "how many" while "nothing" can go with both "how many" and "how much."
How many kids came over today? None
How many times did you see Santa? None.
How much did you pay for the turkey? Nothing.
How much money did you spend? None
How much turkey did you eat? None
But "nothing" usually does NOT go with "how many."