he is not just a sentinel he can lift over 100 tons can travel through time has the ability to rebuild himself so he is very hard to destroy and he has a huge array of weapons from the future he could just go back in time and hunt down bruce banner before he turned into the hulk if it came down to that.
Here's info for those that don't know about Nimrod,
http://www.marveldirectory.com/individuals/n/nimrodii.htm
And yeah, he succeeded in attacking Juggernaut's mind and nervous system with futuristic technology using tight-beam high-frequency sound waves and a synapse dislocator (or however they spelled it) that jammed his neural impulses, although he probably could've avoided it by bringing up his shield. And Nimrod created the Prime Sentinels (I think that's what they were called) as Bastion.
You people act as if Nimrod's a dumbass or somehting. Hulk gets his ass beat down by this future bounty hunter. Nimrod AIN'T YOUR AVERAGE SENTINEL. This thing is from the future. He subdued Juggernaut easily.
Not only does it fight you, it as scans an opponent for weaknesses to exploit and calculates it's battles. Punching the thing ain't gonna work cause it's made up of techno-organic nanonites that constantly repaires the whole.