To compare 2 lists without removing duplicates (in a merge purge setup), add the first list as 'Table Type: Intersection'. Add the second list as 'Table Type: No Purge'. Create an Output table. This output table will be a list of records 'from file2 which matched (intersected) file1.

To match records using in-exact spellings, such as NickNames or Typos...
Instead of using one of the distributed 'basic' matchcodes, go to the Matchcode Editor. Copy or create a matchcode which uses Names. Change the FirstName datatype to First/Nickname by double-clicking FirstName and selecting FirstNickName. Here you can also change the Fuzzy setting for many components from Exact to one of the Near strategies to catch typos, etc.