Here is the full list of all 49 Chromehounds achievements worth 1,000 gamerscore.
Scout experience level maxed out
Commander experience level maxed out
Defender experience level maxed out
Sniper experience level maxed out
Soldier experience level maxed out
H. Gunner experience level maxed out
#1 in total fame for a given period
#1 in seasonal conquest points at end
#1 in avg total fame for a given period
#1 in total conquest pts for period
#1 in average seasonal fame at end
#1 in seasonal fame at end
Deploy to every Battlefield once
Complete all missions in Story Mode
Top marks in every Story Mode mission
Complete Commander arc in Story Mode
Complete H. Gunner arc in Story Mode
Complete Defender arc in Story Mode
Complete Sniper arc in Story Mode
Stay w/ same nation for 3 seasons
Complete Scout arc in Story Mode
Complete Soldier arc in Story Mode
Deploy on hover Chassis 50 times
Win 10 times when outnumbered
Own 1 of each part (except DL parts)
Deploy on bipedal Chassis 50 times
Deploy on multi Chassis 50 times
Destroy enemy HQ and win 100 times
Successfully revive affiliated nation
Donate to affiliate nation 1 times
Destroy enemy HQ and win 50 times
Secure COMBASs total of 300 times
Deploy on inverse Chassis 50 times
Return alive 10 times or more in a row
Deploy total of 300 times or more
Destroy unidentified enemy weapon
Travel total of 1000000
Wipe out enemy and live 100 times
Destroy total of 100 enemy HOUNDs
Attack opponent first 30 times
Win a total of 100 times or more
Secure COMBASs total of 100 times
Destroy 50 or more enemy HOUNDs
Deploy on treaded Chassis 50 times
Deploy on wheeled Chassis 50 times
Win 5 times w/o attacking enemy
Affiliated nation wins Neroimus War
End 5 times in a row w/o killing enemy
Affiliated nation destroys another