May an employee who participates in a qualifed retirement plan and makes a catch up contribution to such retirement plan make a catch-up contribution to a nondeductible IRA in addition to his/her nondeductible IRA contribution?

Absolutely,

Your contributions to an employer-sponsored plan do not affect the amount you can contribute to an IRA. It only affects your ability to deduct those contributions, which seems to be a non-issue for you, based on your question.