https://pokepast.es/8465404989c9bf14
I'm just gonna make this quick
First off, do not use sand veil Garchomp on a sand team. It is fine if it's gen eight since Garchomp can actually sweep but in gen seven, never use it. You will be horribly inconsistent if you do. Next is don't use Magnezone, Heatran, Excadrill and Nihelego on the same team. You do not want to be vulnerable to the Landorus that is prowling at every god damn corner
The only things I'll keep are Tyranitar and Excadrill. Everything else will be dropped from the team
Use this Tyranitar spread. It is meant to outspeed uninvested Rotom while still pressuring defoggers with stab stone miss
If you insist on using Tyranitar's sand, then it's better if you take advantage of Drill's unique qualities, namely rapid spin. It also allows you to compress the role of z user and sweeper
I put Lele on the team because it's just a good fit. Excadrill appreciates it's terrain which protects it against Greninja's shuriken. It's not a good answer but at least it buys you time to revenge kill it, or at the very least, stop it from spamming shuriken
Slowbro and Amoonguss serve as your defensive core. Bro handles the ground types and kills them while Amoonguss is your main Greninja check
Celesteela is to help Slowbro and Amoonguss against the stuff they cannot handle such as Mega Zam, Kartana and Bulu. Also provides a ground immunity which is helpful