For the host discovery I use the simple option
-sn to disable the port scan. The option
P allows to specify the known DHCP IP range, that shorten the host discovery time. After that you may you see active hosts and its assigned IP.
tan@omega:~$ nmap -snP 192.168.1.100-130 Starting Nmap 7.01 ( https://nmap.org ) at 2016-08-05 21:51 CEST Nmap scan report for DNS-320.home (192.168.1.104) Host is up (0.00030s latency). Nmap scan report for android-36517fff78a8bc76.home (192.168.1.112) Host is up (0.061s latency). Nmap scan report for raspberry.home (192.168.1.121) Host is up (0.00052s latency). Nmap scan report for omega.home (192.168.1.123) Host is up (0.00024s latency). Nmap done: 31 IP addresses (4 hosts up) scanned in 1.61 seconds