Thanks for reaching out, @nbmoody! I definitely don't see any major red flags here, so can only recommend additional debugging steps before first doing some of my own research.
The good news is that it seems to still work, despite the warnings. You can run the command helm template my_cluster retool/retool -f values.yaml to see the generated template files and verify that your DB details are being successfully incorporated.
My best guess is that Helm doesn't like the fact that the default value associated with sql in our chart is null, but I can reach out to some folks internally to verify that. Let me know if you're able to move forward or if this is a blocking issue and we can take it from there. 