#1 Too much fertilizer! A Birds nest fern would do very well with a half strength feeding from a water soluble fertilizer. Perhaps twice a year. Your plant is getting too much nitrogen that is producing all the extra fronds!!
#2 it needs to stay evenly moist. In my experience they do not like to go dry. I have a medium sized one underlights and I water it every three or four days.
I can't help with the leggy plant but some one will offer advice soon.