You will need to run through this game at least twice to get this achievement. It can be twice on easy though, so it's not all that bad. All you accomplish during your first run through carries over, including the schematics you've brought to the store, so first you have to make sure to pick up all the weapons so you have them available to upgrade.
In order to get the achievement, you have to power up every weapon in the game, your Rig, and your kinesis and stasis modules using the Benches found throughout the game. Each weapon and suit component requires a certain number of nodes to power up to its max level. All together, you need to collect and/or buy between 150-160 nodes (these cost 10,000 credits a piece at the store) for this achievement (I don't know the exact number).
Do not sell a maxed out weapon back to the store! If you do, you lose all your upgrades on it. I don't know if you need to have everything maxed out concurrently, but I wouldn't risk it! Thanks to d3vilsNight for confirming that selling weapons back will only mean that you have to repurchase and re-outfit that weapon. Do not sell a weapon back to the store!
When powering up weapons and armor, you only need to fill all the spots which grant stats to the item you're upgrading. If you see a blank spot that you don't need to fill, go ahead and skip as it's not necessary for the achievement.
Keep in mind when starting the game over once you've completed it that you have to do so on the same difficulty as your stats will not transfer to a different one if I'm not mistaken. If I am, let me know and I'll update accordingly. :)
A couple of other things to keep in mind (Thanks to x DeadlyFishy x!)
When you finish the game you will be asked to save at the end of the credits. You then need to load that game to start your second run. If you press "New Game" then it will not of the same stats or anything.
Also, Suit level doesn't matter as long as the power node things are filled. You don't have to go and buy that expensive level 6 suit for this achievement.
Another addition to help you through the game (Thanks again to d3vilsNight!)
Upgraded Rigs offer greater Damage Resistance, which you cannot get with Power Nodes. So if you don't have a DLC Rig, you definitely want to upgrade.
xombie25 points out that you can make things just a smidge easier by inputting the following codes for free nodes!
5 power nodes
Press Y, X, Y, X, X, Y, X, X, Y, X, X, Y at start menu
2 power nodes
Press Y, X, X, X, Y at start menu
Mobius Evalon confirmed that 152 nodes are necessary and provided a breakdown of the nodes needed for each item: (thanks!)
The total number of upgrade nodes required is 152. Broken down by item:
Plasma cutter: 17
Pulse rifle: 15
Line gun: 17
Contact beam: 19
Force gun: 19
Kinesis module: 3
Stasis module: 11
DauntingAbyss provided even more codes to help make purchasing nodes go quicker, thanks!:
+5,000 credits (one time only per playthrough)-- X(3), Y, X, Y.
+2,000 credits (one time only per playthrough)-- X(3), Y(2).
+1,000 credits (one time only per playthrough)-- X(3), Y, X.
+10,000 credits (one time only per playthrough)-- X, Y(3), X(2), Y.