yes it's an indoor cat, and there are no other animals. She's been a bit wild lately running around the house, so it's possible she climbed up somewhere she shouldn't have been near something sharp.
She doesn't even seem to recognize she's got a nick... and she is certainly keeping it clean...
I'm not even sure it's a big deal, but I discovered my female cat has a slightly torn nipple that looks like is is about halfway off, but slightly scabbed over and done bleeding. She is fixed, so there are no nursing needs/concerns.
I think she may have licked/chewed it as the cause, but it is...