Technically it is available more or less right now (see splatoon 2 hacks), and the thing that allows you to run custom games/overwrite a game with another and in doing so bypass checks would allow you to stick your own instructions in.
As far as something you would recognise as a cheat engine (think peek and poke, maybe full dump as well), not necessarily a fully developed one with all the nice compares built in... no idea. We have the access and the in for it all, however it seems like we might see something like the 3ds scene again where various anti piracy/cheats/fun people will do many of the core hacks, those wanting the fun stuff maybe coming in later. On the other have if TX are doing what they do then whenever they get around to it. Similarly someone could patch a kernel or relevant service tomorrow.