I like to see the top games being dominated by Nintendo titles, I am sure it annoys people and I am wondering why they have had a long run up there. 

True Crash is young, but from what we've seen that doesn't seem to be changing. 

What are your conditions? Do Splatoon, Zelda, Mario Kart, ARMS, Pokémon SuMo, at least one version of GTA5, and Crash all have to be in the chart? If so, ARMS will probably leave the chart at least once before the end of August, which will end the streak.

On the other hand, if you only need one of those games to be in the chart at any given time, then we probably won't see the streak broken for over a year.

Crash should drop pretty soon. We'll see on NPD if it's still high there, but I think its legs will drop by the end of September.
GTA will remain there as long as PS4s and XBOs are sold.
Sun and Moom will disappear inmediately when the holidays begin or when US/UM releases.
Switch titles is hard to tell. BotW is the main system seller in the US, Mario Kart is a big seller overall and Spla2n is an astronomycal seller in Japan. I can see Odyssey replacing MK8D (MK8 is a port and people might expect a MK9), but I think as long as the Swtch sells, those main 4 sellers will be pretty high.

Probably only when GTA VI releases as a cross gen game again in 2019 or 2020. xD 

GTA V will unfortunately never drop this gen because every week there's at least a few thousand 12 years old who have their balls drop and ask momey for that big boy game.

Crash will probably remain in the UK chart for a while but worldwide top 10? It will drop most likely in 3-4 weeks

Sun and Moon will drop a short while after Ultra Sun and Ultra Moon, then those will stay up there till about may 2018

Zelda will stay up there till mid 2018. Mario Kart 8 won't drop till mid 2018. Arms will stay up there till most likely November of this year, but then it will get a resurgence depending on if American sales are decent at Holiday(Japan loves it).

GTA V is hanging there few years now, so not anytime soon (maybe until GTA6 urives, lol).
Zelda BotW and MK8D are must have games for Switch, so I imagine they will stay in top 10 at leats untily years end. New Pokemon is coming soon so Sun/Moon will probably go down.
Crash/Splatoon 2 are still too young, but we could have Splatoon 2 hanging in there for quite time also because its selling around 50k per week in Japan alone. ARMS will drop in few weeks.

Zelda and Mario Kart will be perched in the top 10 for a while. Not sure about Splat 2, and ARMS will drop out in a few weeks.

GTA V might drop for a few weeks when Red Dead 2 releases, but I don't see it fall from a top 20 either. After RDR2's had it's spotlight, GTA V will return.

Well, there might be a time when GTA VI drops.