Tolerance display in drawing mode is controlled by your .dtl file. Click Advanced > Draw Setup and set tol_display to yes.
You probably want all your dimensions set to a tolerance mode of normal and the one you're interested in set to the appropriate mode. Your tolerance mode is controlled by the config.pro option tol_mode IIRC. Depending on what value it's currently set for, you may have to change the tolerance mode of all the dimensions to nominal.