Can't find a wireless access point's IP address after changing router IP/LAN settings

The access point's IP address is probably still 192.168.0.10, since you didn't change it. That makes it unreachable by IP. Normally, an access point only has an IP address for configuration purposes, so with an IP address that's unreachable, you probably can't configure it. Data will still pass through it just fine though.

If you temporarily assign a PC connected to the access point an additional IP address that can reach the AP, such as 192.168.0.55, you can then reach the AP on its old IP address. That should allow you to correct the IP address to one that is inside the new LAN address range.

Run

arp -a 

and you will get all the IPs and corresponding MAC addresses. You need to check the corresponding MAC address on the network, but nmap tells witch one is the AP.