That's not true. Per the State of NJ, if a taxpayer earned income from NJ while both a resident/nonresident they are required to file both NJ-1040 and NJ-1040NR with the State of NJ. I don't think ProConnect has the ability to process.

"If you received income from New Jersey sources during both your residency and nonresidency periods, you must file both a NJ-1040 and a NJ-1040NR. You must report the income you received during the time you were a resident on your resident return. Report the income received while you were a nonresident on your nonresident return."