I want to use Nominal Group Technique in my study because of the small scale of respondent. Can I use the existing survey instrument for voting session in NGT? What about the previous steps? Any reference available?
If you are going to bring the participants together, I am not sure why you would use a nominal group rather than a focus group. One compromise option is to begin by having each person generate a "candidate item" then have the group as a whole discuss the strengths and weaknesses of the different items.
Whatever option you choose, I would still have a small set of people do cognitive testing on the items that you develop.