Convert volume ROI to surface using fsaverage template

Dear Neurostar community,

I have a ROI.nii volume file. I would like to do a functional connectivity analysis with this ROI, but in surface space using the CONN toolbox.

Can anyone suggest as to how to convert an ROI volume file to a surface label that can be used with the fsaverage template?

Thank you,

Nilearn has a routine to project volume data to the surface.
I guess you can use it to obtain a map on fsaverage.