error doing DNS lookup for NS records for "xyz.testexample.com": lookup xyz.testexample.com on 192.168.0.1:53: no such host

That error means Kops is unable to resolve the DNS name xyz.testexample.com.

DNS names in Kops are a critical path. Please check the resolving on your PC. Managing the cluster will be impossible without a correct resolving.

What about creating a new cluster with private DNS (I see in comments that you tried to do it) - check that how-to, you need the path "Using Public/Private DNS (Kops 1.5+)".