If by wing nut you mean the knob that is on the opposite end from the q/r lever, no that generally should not turn freely, though there are some rare levers that have a cover on them. Leave the wheel in place and remove the q/r lever completely. Check to make sure the q/r springs have the large end toward the outside, the small end toward the center of the hub. Also, the end of the axle should not protrude past the dropout that it is sitting in, which is the most likely problem. The locknut for that side may have backed off. You would need a cone wrench and perhaps in-person assistance to tighten the locknut and adjust the hub.