Looking at it tacticaly not many kicks from TKD will work enough times to warrent their inclusion.In a fight anything can happen and if the oppurtunity arrises then anything can be done in that split second.
Yet there are things being done that work against the best fighters in the world.Things that happen often and work and so these are the things that people will train if they want to beat the best.

Looking more at the skip side kick,I dont think it would work well because of the risk of takedowns.Not only after kicking but at any time.The stance you need to take for a NHB fight is more square than for a stand up fight so the lead leg would not be in a good position to pop the kick out....the front leg isnt that further forward than the back leg...not compared to a TKD stance which is more side on some fighters even virtualy side on....and if the kick is learnt whilst in a side on stance its asking lots to do the same kick well from a more square stance.It would take too long fortheleg to reach the target and your giving the opponent your hips...and what about recovery if you miss or he steps back? It wouldbe too vunerable.

A front kick with more hip that turns to a side at the end might be the closest thing to a side kick worth doing in an NHB fight.(more to push them away than strike)

Same for the other kicks.The start position is important.The TKD stance and lack of worry for takedowns makes it ok to use lots of hip rotation and knee chambers and snaps yet for NHB its not good.The kicks become more awkward to do that way because of the stance needed and the lack of time available.Also the body mechanics change and the way to gain power changes.

A thing with martial arts I find is there is lots we WANT to be able to use andfor it to work...its the big question...what works?Yet for NHB or real world it has to be what actualy, truthfully works that is prefered.
I point my saxaphone at the rare Booted Gorilla.