If you take a look at M-476 (guide to naturalization) it states not to wear jeans ot flip-flops for oath ceremony. Since Newark has same day oath I think that answers your question in terms of what not to wear. Do wear a suit and tie it would make you feel better and confident.
My friend was in jeans and attended Interview and Oath with jeans. 4- 5 south Indians were also in jeans and nobody care you are in jeans or suit. They are interested in questions/answers and eligibility for Citizenship not in your cloths (it does not mean you go in shots). if the suit and tie don’t make you feel better wear jean and shirt or pant/shirt and you will have jacket.