I've been working on getting ds1 to nap in his cot. He's never done well at it, but we've been having some success since he developed an attachment to a cuddly. He cuddles it at bedtime (bedtimes fine)
He's 21months nearly, one nap a day. Very occasionally two shorter ones (if in car) or none.
Was taking an hour of complaining to go to sleep in the cot fir the nap, not crying, and better without me in the room. Not doing this every day but when we are at home. Got down to much less time, not exactly sure as not in the room with him but much quieter quicker, less complaining. He's started chucking his comforter out though, did it today with both things he loves, as I wasn't in the room I just thought he was complaining more than usual, sneaked a peak and they were both out. Gave them.back, chucked them out. Repeat. Worked himself into a state. Finally laid down with his favourite and slept.
Not sure how to approach it? Keep giving them back? It took an hour again today, but he usually sleeps for two.