As @JJX already said you can provide login credentials inurl to your dashboard as a oneliner.
But bevore you start, please create a View Only user for this and do not use a user with admin privileges!!!
Quick Example:
You can also do this for your NagVis Maps like this:
Besides from that you can try to use the Grafana Integration with CheckMK if you want. I thinks it’s currently WIP but you can already try it. Take a look at → GitHub - tribe29/grafana-checkmk-datasource: CheckMK data source for Grafana
Maybe this meets your requirements.
Or you work with the API of CheckMK and build your own thing.
I hope this helps a bit