Oh gotcha! Yeah, git merge upstreamNane branchName is the right method. Just be aware that you might have a whole host of conflicts to resolve if there’s been a significant amount of time in your branch.
One thing I like doing is creating a feature branch, then branching off that for very specific feature work. Then I try to complete that feature quickly and merge that into my feature branch and keep that up to date every day with the updated branch it was forked from. That way, I’m never too far behind production changes and the merge conflicts are kept at a minimum.