I think the energy costs normally shows up in the tooltip automatically when you set an energy cost in the Cost - Vitals field under units and the energy cost shows for any other abilities that I've made thus far but for some reason it's not working for this particular ability. I'm still very new to the editor so maybe I just missed some other field. What other fields would affect the energy cost showing up or not showing up on the tooltips? Thank you in advance.

Sounds weird indeed.
Try to look for something under "Button" in the Data Editor maybe? I really don't know.

As far as I know unless the ability costs no energy at all, it should show up. I do recall seeing some option to disable costs on tooltips, but I don't remember if that was client-based (like hotkeys being visible) or if that is changed in the map itself.

Yea, I think it's just some editor issue with the name Ensnare in Buttons. I remade the button from scratch and named it Ensnare again and the energy cost didn't show up still so I changed the button name to EnsnareBW and it voila, energy costs are in.

Buttons have flags to control what is displayed in the tooltip. But I'm not sure if that is fully working, yet.