How do you get your toddlers to poop on the potty?!

My 3 year old is great for peeing in the potty but will not poo. She will wait until we are about to put her in bed and poop in the bedtime nappy.

We have tried bribery and rewarding her trying and farting on the potty. She has watched me poop on “the big potty”.

It is always at night when she will poop which is why we wait for the last moment to put her night nappy on. Will this pass or what else can I try?