He probably does not want to nap because it is a weekend and everyone else is still up, and he doesnt' want to miss out.
But he IS tired... and fussy, and needs a nap.
So... you can keep to a regular nap time routine... and, at that time... make EVERYTHING BORING... and you/Hubby, make quiet too. Tell him EVERYONE is going to nap. Don't talk about that you/Hubby are going to be doing stuff while he is sleeping. Make everything quiet.
Let him unwind first.
Don't get him real active right before nap. Toddlers need to wind-down first.
Do something that will key him down, prior.
Then transition him... not just plunk him down into his bed suddenly. Or he will resist.
Transition him.... about 1 hour before nap time, verbally cue him... tell him, after lunch and play, it is nap time and WE will get ready. Not 'you get ready." Make it a "we" thing. Then he won't feel he is getting ousted.
For me, I ALSO explain to my kids, that being 'tired' is NOT a 'bad' thing.... it is human. We all need a nap and get tired. But we can say it.... it is knowing yourself. So, my kids don't DREAD naps and actually will say when they are tired and want to nap.
Both my kids are now 4 and 7... and they both still nap. My son every afternoon. And my daughter whenever she needs it.
They don't battle about it.
I taught them that.
That 'naps' are NOT a 'bad' thing... and that it is okay to feel tired, if need be, they can tell me.
My kids still go to bed at night fine, and can fall asleep fine. Despite napping.
Also, over-tired kids actually have a HARDER time falling asleep. THAT is probably why, at night, he has a HARD time sleeping.
Over-tired kids, actually have a harder time falling asleep, staying asleep, and wake more at night and don't get a good rest.
And some over-tired kids.... actually get more 'hyper' when they are tired.
all the best,
Susan