Yes we can! It’s slang anyway so I don’t think it will matter making it plural

My immediate answer was the same as Simon White's, but I like to test usage questions by searching Google News. Why Google _News?_ Because it is a corpus of contemporary English that has passed copy editors and made it into print. It includes columnists and feature article, so it uses both formal "good English" and informal "conversational English." I easily found examples of actual use: "5 Medicare Part D "Gotchas" To Avoid" --TheStreet, a well-known financial website) "ANDREA WOROCH: Don't fall for these 5 Black Friday gotchas"--Columnist in a small-city newspaper, the Bakersfield Californian "6 legal 'gotchas' that could sink your CIO career"--CIO magazine

Thanks Dan, I’ve never heard of Google News and it seems to be really useful.

I'm not sure what you mean by "GOTCHA" so it's hard for me to give an answer. However, I notice you capitalized GOTCHA and GOTCHAS. Is this intentional? Is GOTCHA an acronym? And finally, if GOTCHA is an acronym, making it plural should just require a lower case s, rather than another capital letter.