If I bought groceries in Nevada and live in California, Do I have to pay taxes on that under Out of state purchases

It depends.  Most states, when considering tax on out-of-state purchases, follow a pattern like this:

1. Is the item you purchased taxable in California? (If no, stop.  You don't need to report it)
2. Is the item for use in California?  (If no, stop.  You don't need to report it)
3. Was the item taxed where you purchased it?  (If no, continue to 4) If taxed, was the out-of-state tax equal to or greater than California sales tax?  (If yes, stop.  You don't need to report it)
4. Report the amount of the purchase, and then report the amount of tax you paid in the other state at the time of purchase.

The difference is reported to and taxed on your California return.

In your case, the question is whether the groceries purchased in Nevada are taxable in California.  If they are, you purchased the groceries for use in California, and you did not pay the same amount of tax (or no tax) in Nevada for the groceries, you would owe CA sales tax on the items.  Otherwise, you do not need to report them.