Yes, you can choose a niche.
Immediately you activate the marketplace module, you have all the categories by default. However, you can select the particular category or categories that you need. Here's how to go about it:
Step 1: Visit commissions.ng/login to login to your dashboard.
Step 2: Click on "My websites" icon and Select your website
Step 3: Click on "Settings"
Step 4: Click on the "products shown"
Step 5: Select the categories you want. Uncheck the categories of products you don't want to appear on your website.
Step 6: Save your edits.