Nina doing it definitely wouldn't have been either but I am fine with them switching it up from time to time and the person who did something bad confessing can be soapy. You hate Erica Kane but one of the most soapy moments was when she confessed to Maria that the baby she adopted was in fact, her baby that she thought had died. She had to convince her of it because Erica had covered her tracks beautifully.
For it to have truly been soapy, it would have happened at that NYE party in front of a room full of people. I really thought as loud as Lois was talking, Sonny was going to be standing behind her ala the way Spencer found out Nikolas boinked Esme.
