When creating many of the same type of form field, the quickest and easiest method is to use the Make Copies tool. Just setup the form field with the appearance and other properties you’d like all the fields to be like and then chose how many rows and columns you want.

To create a batch of similar fields:

1. Open the PDF in Nitro Pro
2. Create the exact form field you’d like to copy
3. Select the form field
4. On the Properties context tab, in the Tasks group, click Make Copies
5. Choose the number of rows and columns of fields you’d like to create