Landorus may be a good option, but I don't know about Terrakion. I understand that he is a really good Poke to Chomp's checks, but having 3 Physical Attackers isn't the best, IMO (I am assuming Chomp is going to be a Physical Attacker). Honestly, I think he should have a Physical Wall oppose to another Attacker, and IMO, Gliscor is a good option, as he benefits from the Sand. Even though, Terrakion isn't a bad choice, as he is pretty bulky on both ends. But then, he has to use a Poke that can get rid of Ground Types, as they will destroy him, as can be said about using the Gliscor & Chomp combo against Ice. Also, I do agree with others that Aegislash or another steel type would probably be a good option to deal with Ice Attacks, even though Aegislash is also yet another Physical Attacker but has great defenses.
I am under the assumption that this is not meant to be a stall team. While Gliscor may help with Fighting-types that threaten Tyranitar, the team needs offensive synergy first and foremost. Gliscor doesn't do anything in that regard. In fact, it makes matters worse by worsening the team's ability to deal with Skarmory, which is the only common defensive Pokemon that can take on Chomp. Additionally, I don't see what the problem is with having three physical attackers. Chomp obliterates any physical walls not named Skarm, and even Skarm can barely take a hit:
+2 252 Atk Sand Force Mega Garchomp Stone Edge vs. 252 HP / 232+ Def Skarmory in Sand: 199-235 (59.5 - 70.3%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
+2 252 Atk Mega Garchomp Stone Edge vs. 252 HP / 232+ Def Skarmory: 153-181 (45.8 - 54.1%) -- 96.1% chance to 2HKO after Stealth Rock and Leftovers recovery
Skarm's only method of dealing with Chomp is Whirlwind. If the Chomp user plays their cards right, they can keep enough offensive pressure on the opposing team to prevent Skarm from healing. All Terra or Lando has to do is clean up what Chomp left behind (or the other way around). Point being, Chomp and Terra or Lando would provide enough offensive power to get by most physical walls, regardless of whether they're physical or special attackers.
Anyway, as Zekrom pointed out, Magnezone would also be a suitable teammate due to its ability to trap Skarm. I'm not sure if it would be necessary to have if OP decides to use Terra or Lando, but it's definitely a worthy consideration nonetheless.