My friend was arrested in 2016 in the state of Arkansas and charged for ASSAULT DOMESTIC 3RD DEGREE and was given one year before sentence. The case was decided in 2018 as: NOL PROSSED

She has been the lawful resident for 7 years now, and she doesn't have any other criminal records besides that I just mentioned..

My question is:
1. Should she worried about her citizenship application because of this?
2. How will this affect her naturalization process
3. Does she need lawyer for this or she can simply represent herself and be fine.

I appreciate your help in advance