1ashgarg, yes you do
The connection profile is what NCM uses to login to your switch.
During automated or manually initiated tasks such as upload\download config, NCM needs to login to the switch in a telnet\SSH session similar to the way you would, to execute the commands
You need to define the admin username and password as well as enable password (if applicable) in the connection profile so that NCM can "parse" these credentials when the switch OS prompts during the telnet login.
If you have different admin usernames and passwords, you should create different connection profiles and assign the relevant one to the respective nodes in NCM. I might be subject to correction in this as I only use 1 admin and enable password on all my nodes.