There's nothing wrong with listing a nondischargeable debt, although it shouldn't make any difference whether or not you list it. It would be much more relevant to Chapter 13, where your ability to repay your other debts could be affected, particularly if the 401k retirement loan includes an acceleration clause making the entire balance due if a payment is missed.
You are repaying the 401k loan through automatic payroll deductions? If so, if it were me I would personally list the loan and also listing the payments on my Schedule I.

