Most chins will not pee outside their pee pan. Mine have the full floor or their cages to pee and they all pick a spot. So it's easy to find the spot and put a litter pan there if you didn't want to fill the whole floor with shavings.
When mine are out for play they have a pee pan on the floor that they will use.
I have one fella out in the laundry room one night washing off his shelves with no pee pan around. I noticed him scooting around like he was looking for something when he sat on the metal dust pan & pees.
Had the same chins out for a trip to the feed shop one day, and when I got back I was stood up chatting with hubby about our little adventure when he started getting really antsy, just as I asked him what was his problem, he peed on me.
I just wasn't listening when he was trying to tell me.
Chins are much like cats that way, and will only pee outside a litter pan if they have too.
Now there is the exception to every rule, so don't freak if one doesn't get it