Thanks. So I know how to pass variables like in your example, but the issue was that the initial command I was using reg query for would print out multiple lines, but only display the Results like so "End of search: 1 match(es) found." instead of the key that I actually want. The guy in that thread was able to assist me and from there I was able to then pass the variable to reg add without any issues.
for /f "tokens=*" %%A in ('reg query HKLM\SYSTEM\ControlSet001\Services /K /F bomgar-scc /S^| find /V "End of search"') do (
Set "BomgarService=%%A"
)
echo %BomgarService%
The " find /V "End of search"" was what I didn't know how to do, but it looks like it filters out that line so then it displays the key which is exactly what I needed.