Why am I getting inconsistent outputs for nslookup and dig?

Issue

• Why do I not get the dig output when I dig without the FQDN of the node ?
• Why am I getting inconsistent output when I dig a node in my environment as compared to the nslookup command for the same node?
• node1,node2 are DNS clients while node3 is my DNS server. Consider the below :

[root@node1 ~]# dig node2.example.com +short =====> I get the expected answer when I use the FQDN while querying.
192.168.122.161
[root@node1 ~]# dig node2 +short ==============> I do not get the expected answer when I do not use the FQDN while querying. 

I get consistent outputs with nslookup command no matter whether I use the FQDN or not.

[root@node1 ~]# nslookup node2.example.com =====> I get the expected answer when I use the FQDN while querying.
Server:        192.168.122.170
Address:    192.168.122.170#53

Name:    node2.example.com
Address: 192.168.122.161

[root@node1 ~]# nslookup node2  =============> I again get the expected answer when I DO NOT use the FQDN while querying (unlike in the case of dig command).
Server:        192.168.122.170
Address:    192.168.122.170#53

Name:    node2.example.com
Address: 192.168.122.161

[root@node1 ~]# hostname
node1
[root@node1 ~]# hostname -f
node1.example.com