The example NMState instance in the operator manifest is incorrect. It currently has the nodeSelector as a string. It needs to be represented as an object. Without fixing this, one must click to yaml view to edit the spec. Once fixed, a user could then just accept the default without intervention.
Verified on Client Version: 4.7.0-0.nightly-2021-02-01-180932 Server Version: 4.7.0-0.nightly-2021-02-02-223803 Kubernetes Version: v1.20.0+3d0efee
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: OpenShift Container Platform 4.7.0 security, bug fix, and enhancement update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2020:5633