Need Script to find SP Invoked in SQL
The SQL Server Agent job definitions are stored in the msdb database, in the sysjobs and sysjobsteps tables. You could do a plaintext search on those tables with the following query:

SELECT *
FROM msdb.dbo.sysjobsteps
WHERE subsystem='TSQL' AND
      command LIKE '%nameofmyprocedure%'


Note that there are still cases when your stored procedure still won't show up.


If there's another stored procedure run by the job that, in turn, launches the stored procedure you're looking for
If an SSIS package launches the stored procedure
If the procedure isn't launched by SQL Server Agent, but by some other scheduler task