S.H.
When a kid is 2 years old, sleep/nap tweaks often happens.
But if he is tired, and usually a kid is, then they need a nap.
By doing a regular daily routine.
Also, get him out in the mornings for run around time. Boys are very physical and need that. They need to expend energy, physically.
THEN, after that, come home, have a lunch, then nap time.
Tell him verbally, ahead of time... what is coming up.
ie: we're going to the park, then coming home to eat lunch, then its nap time.
Verbally cue him. Kids need to KNOW what is coming up. Not it being just plopped onto them with no warning.
Then they can transition better.
That is what I do with my kids.
My son just turned 4 and my daughter is 7.
My son still naps everyday in the afternoon. And has napped everyday, since he was a baby. He needs it. If not, he gets MEGA overtired and fussy. He can't last all day without a nap.
My daughter- she will nap when she is tired. That is her routine.
I have no battles about naps.
It is routine.
It just is.
I verbally cue them... they know the routine. It is autopilot for them.
I also taught them that being tired or 'napping' is NOT a 'bad' thing... but it helps their body grow and be strong. I make it 'positive' for them and explain it. I don't treat it like a 'bad' thing.
Observe your son's cues and sleepy signals. When he is tired, then he's tired. And need a nap.
Lay with him if you have to. Or sit in the room. Don't engage or talk. Just sit there. Tell him 'nap now...' and let him unwind.
I would have daily outdoor activities for him in the morning. Then by 11:00, or earlier, go home, have a calm lunch, wind-down, make everything quiet and turned off... then transition him to nap. Make the atmosphere calm and quiet.
I also sometimes tell my kids that "Mommy is going to nap too..." and then I get ready with them. And then I DO nap. We all nap sometimes.
try to synchronize your son's nap, with your baby's afternoon nap.
that is what I did too, when I had my 2nd child. It worked.
just some ideas,
all the best,
Susan