The nurse should check with the transgender patient and sensitively ask if everything is OK. If the transgender patient has heard any of the discussions it is imperative that she is given every assurance that the matter will be dealt with. If the transgender patient is visibly upset and there is spare capacity it would be appropriate to offer her the option to move to a single room, although this must be with the patient in mind rather than conflict avoidance. (Only one of the patients is 'in mind' here)
General appreciation of transgender issues is very low in our communities and often this is used as a rationale for behaviour that is essentially transphobic. (What, not wanting to be in a single-sex ward with someone who is of the other sex?)
Here we go people, that famliar strawman... If a white woman complained to a nurse about sharing a ward with a black person, or a heterosexual male complained about being in a ward with a gay man we would expect our staff to behave in a manor [sic] that deals with the behaviour immediately.
Therefore, if a woman on a single-sex ward complains about being in a ward with a person with a penis, deal with it immediately. (And yes, Mx Quentin, we're focusing on the penis here! But not yours!)