Here is the full list of all 53 Nelo achievements.
Open 5 node gates.
Complete Chapter 3 in Campaign.
Kill 400 enemies using only light melee attacks.
Kill 400 enemies using Melee attacks.
Complete Chapter 2 in Campaign.
Complete Chapter 1 in Campaign.
Kill 400 enemies in Omnifire.
Kill 400 enemies on a Quasar buff.
Kill 400 enemies while in the air.
Activate level 3 shield 100 times.
Kill 400 enemies using your guns during Melee attacks.
Get through a stealth section without getting detected by patrol.
Survive enemy waves from a patrol ship 25 times.
Open 10 node gates.
Kill 400 enemies using Aim.
Get to Zen level 3 25 times.
Find 8 mission logs.
Find 18 mission logs.
Find All hidden mission logs.
Kill 100 enemies by throwing them.
Kill 200 enemies by throwing them.
Kill 400 enemies by throwing them.
Get 100 S Ranks from fighting Nightsithe Waves.
Set off 500 bombs.
Set off 100 bombs.
Defeat the Gorgon Skull.
Defeated the Harpy Talon.
Kill 800 enemies in Omnifire.
Defeated the Kraken Spine.
Hug your Brother.
efeated the Nightsithe Carrier with the Hyper Cannon.
Defeated a wave of Nightsithe bombers with one of the White Blazar's turrets.
Kill 50 enemies while manning a Mech suit.
Defended a Plemnibon hideout from Nightsithe Invaders.
Pilot a Tono Gian Starfighter.
Get devouered by Nightsithe Leviathan 5 times.
Skipped all Cinematics.
Watched all cinematics without skipping.
Complete Chapter 4 in Campaign.
Complete Chapter 5 in Campaign.
Complete Chapter 6 in Campaign.
Complete Chapter 7 in Campaign.
Complete Chapter 8 in Campaign.
Complete Chapter 9 in Campaign.
Complete Chapter 10 in Campaign.
Complete Chapter 11 in Campaign.
Complete Chapter 12 in Campaign.
Complete Act 1 in Campaign on Recuit Difficulty.
Complete Act 1 in Campaign on Adept Difficulty.
Complete Act 1 in Campaign on Hero Difficulty.
Complete Act 1 in Campaign on Legend Difficulty.
Complete Act 1 in Campaign on Myth Difficulty.
Complete Act 1 in Campaign on Sublime Difficulty.