I for all the charizard that I have gotten to been there will have changed the nest of the area for that there is always charmander. Good luck
You can always use The Silph Road | Pokemon GO Resources to look for nests near your area. Since nests change now and then theSilphRoad it's always updated (reports are chsnged every migration)
I can confirm central park has lots of them. I have been catching at least 20 of them in the past few hours.
wow the whole F****ng park is full of charmanders today i catched more dan 50 charmanders as you look at silph road you see 4 or 5 nests in central park now i got a good charizard now and i still have 146 candies to wait for another good IV charmander edit : LOL as i wrote this i catched 6 charmanders , and 1 of them is level 25 CP 673 IV 93 nice nice