Here is the full list of all 62 Nexomon achievements worth 1,000 gamerscore. It takes around 30-35 hours to unlock all of the achievements on Xbox One.
Collect all monsters. A true master!
Capture the legendary Plant-type Nexomon, Nara.
Capture the ultimate Nexomon, Omnicron.
Capture the legendary Wind-type Nexomon, Ventra.
Capture the legendary Mineral-type Nexomon, Grunda.
Capture the legendary Warden of Wind, Hexia.
Capture the legendary Warden of Water, Darine.
Capture the legendary Warden of Thunder, Krowr.
Capture the legendary Warden of Mineral, Titan.
Capture the legendary Warden of Plant, Tikala.
Capture 300 wild Nexomon.
Capture the legendary Warden of Fire, Ogoon.
Capture the legendary Fire-type Nexomon, Fona.
Capture the legendary Water-type Nexomon, Arqua.
Own a level 99 or above reborn Nexomon.
Capture the legendary mystery, Metta.
Own a level 60 or above reborn Nexomon.
Capture the legendary Electric-type Nexomon, Luxa.
Collect all 41 Nexomon fragments and get the radar.
Defeat Omnicron (again) and save the world (again). Congratulations!
Defeat the Warden of Wind, Hexia.
Defeat the Warden of Thunder, Krowr.
Defeat the Warden of Mineral, Titan.
Defeat the Warden of Fire, Ogoon.
Defeat the Warden of Water, Darine.
Own a level 30 or above reborn Nexomon.
Own a level 99 or above Nexomon.
Enter the mysterious Netherworld and complete your mission.
Battle Omnicron and become the new Nexolord!
Defeat Omnicron in the ultimate battle.
Defeat Zetta, the raging thunder.
Defeat Fenrir, the embodiment of pride.
Defeat Overseer Glacia, the jealous one.
Defeat all tamers.
Defeat Grunda, the underground beast.
Defeat Merida, the terror of the ocean.
Capture 240 wild Nexomon.
Own a level 60 or above Nexomon.
Defeat 20 tamers.
Wasn't it obvious?
Defeat Merida in a volleyball match! Easiest win ever.
Defeat Overseer Hilda, master of the paranormal.
Capture 180 wild Nexomon.
Defeat Nadine, the sky menace.
Capture 120 wild Nexomon.
Defeat Overseer Ira, the fire rocker.
Own a level 30 or above Nexomon.
Win 500 battles on your adventure.
Win 400 battles on your adventure.
Defeat 10 tamers.
Capture 60 wild Nexomon.
Defeat Overseer Remus, a man who knows no fear!
Win 300 battles on your adventure.
Win 200 battles on your adventure.
Capture 30 wild Nexomon.
Defeat Overseer Ivan. That's hardly an accomplishment, though...
Win 100 battles on your adventure.
Capture 10 wild Nexomon.
Win your first tamer battle.
Catch your very first Nexomon.
Win your first Nexomon battle.
Get your very first Nexomon. Now go and save the world, champ!