Do you have a good guide on how signoz can pick up nginx-ingress logs and format them in a good way, not just like everything in the body. would be awesome if you could filter on request type, http response code and so on.

You will have to use pipelines to parse them using regex https://signoz.io/docs/logs-pipelines/introduction/

Nice, I will have a look. I'm guessing this is applicable on selfhosted k8s?

Yes should work on selfhosted as well