I am running ERS/ERD analysis using Morlet waveform.
Would it be possible to get a ERS/ERD plot for one channel for example C3?
Yes.
Follow the introduction tutorials, and the time-frequency section will teach you how to do that.
https://neuroimage.usc.edu/brainstorm/Tutorials
https://neuroimage.usc.edu/brainstorm/Tutorials/TimeFrequency#MEG_recordings:_Single_trials