Warhammer 40,000: Space Marine
35 Achievements
The Bigger They Are...
Kill 25 Ork Nobs.
36.2%
How to unlock the The Bigger They Are... achievement in Warhammer 40,000: Space Marine - Definitive Guide
Mickey Burns
TrueAchievements
TrueAchievements
After meeting up with both team members and running the trench towards the bunker, you will come across a group of marines making a stand. After a few dropship waves, an Ork Nob will be dropped into battle.
Repeatedly stun combo him (x,y or x,x,y or x,x,x,y) until you can struggle with him in which you can repeatedly tap b and work towards
The Nob Down achievement in Warhammer 40,000: Space Marine worth 32 pointsWin 10 struggles against the Ork Nob.
Reload the checkpoint until you get the achievement.
jamby, BlackDevil990
Ork Nobs are the large Orks that when you attack and engage in an execution you'll go into a "struggle" with them (pressing the 
button). They are usually large, red, and have a 2 handed weapon. Around chapter 7 you'll start to fight Shoota Nobs which are large, black, and have a larger gun. You will still enter the "struggle" with them if you attempt to execute them.
Nobs are the big guys you see starting on the second mission that take a metric ton of damage before finally going into a 'stunned' state where they may be killed. They deal massive damage in melee, so unless you activate FURY, it would be best to engage them at range.
Starting around Chapters 6 and 7, you will start seeing Shoota Nobs, these Nobs are simply a larger version of the basic Shoota Boyz. Shoot them as normal while you can, and when you see them pause to reload their guns or to unjam their guns, charge forwards and engage them in melee.
Once they are stunned, aproach them and press 
to enter a button mashing sequence to execute them and regain any health you may have lost in the fight.