Is there anyone that wasn't irritated while attempting to break into those chests' padlocks and wasting his picklocks? I doubt. That's why I created this list that includes every chest code in the game. Well, almost every, because, in fact, a part of chests in Gothic 2 are not worth visiting.
L = press left while opening chest, R = press right
  
~~NEW WORLD~~
  KHORINIS, LOWER TOWN & PORT
  Masters (Bosper, Matteo, Thorben, Harad, Constantino) - L R R L R 
  Daron, Zuris - L R R L R L L 
  Andre, Ruga - R L L R 
  Barraks - R L L R R R 
  Lehmar - L R R L R 
  Brahim - L L R R L R 
  Bromor - R L R R R R 
  Ignaz - L L 
  East gate tower - R L L R R L 
  South gate tower  - R L L R R L 
  
  KHORINIS, UPPER TOWN
  Going from right side to left:
  1 house - R R L R R L 
  2 house - L L R R L L 
  3 house - L R R L R L L 
  4 house - R L R R 
  Lord Hagen - 8x R 
5 house - L R R L
   
  THIEVES’ GUILD
  "Dark room full of rats" - R R L L R 
  Cassia - L R L L R R 
  Ramirez (from left) - R R R L L R , L L L R , L R R R L L 
  Closed room - R R R L R R R L R L R L R R L L L R R L 
   
  BEACHES
  1 - R L L R L L 
  2 - R L L R R L L L R R R 
   
  ISLAND - R L L R R R L 
   
   
  ONAR’S FARM
  Bennet - L R L R R 
  Onar - R R L L 
  Maria - L R L R L R R 
  Lee (at night) - R L L R R L 
  Khaled (from left) - L R R R L , R R L R L L R 
   
  MONASTERY
  Gorax - L R 
  East Mages Room (from right) - L R R L L R , R L R L R 
  West Mages Room (from right) - R L L R R R L , L R L L R R R 
  Vault - R L R R L R 
  Pantry - L R L R R L 
  
  CAVES
  Cave of bandits (west from town) - R L L R 
  Cave of molerats under the bridge - L R L L L 
  Cave of orc near the town - L R R L R 
  Cave on the way to Black Troll - L R R L R 
  Cave behind the doors, near the Ring - L R R R L 
  Cave near the Pyramids (from left) - R L L R L R , L L R R L L R 
  Cave near Onar’s Farm (from right) - L R R L L L , R L R R L R 
  Cave of zombies near Dexter (from right) - L L R R L , R L L R R L , L R R L R L R L 
  Sagitta (from right) - R L L R , L L R R 
  Secret Distillery - R R L R L 
   
  OTHER
  Orlan’s Inn - R R L R L 
  Safe near the bridge - R L L R R L 
  Dragomir (from right) - L R L R , R L L R L L R 
  Pyramids, big - R L L R R R L , small - L R L R L R 
  Grom - L R R L 
  Elvrich (from left) - L R L R R L , L L R R R L 
  Under Dexter’s Bridge - L R L R L 
  Dexter - L R L R R R L , L R L R R , L R R L L L R R 
  Pass - L R R L , R L R R L 
  Saturas - L R R L R R L 
   
   * * * * *  * * *
  ~~OLD WORLD~~
   
  CASTLE
  Main building:
  Garond - R L L L L R 
  level up (from left) - R L L R L , R R L R L R L , L R L R R R , R L L R R R L , 6xR , R 6xL 
  Angar - L R 
  Milten - L R L R 
  Warehouse (from right) - R L L R R R L , L R R L R , L R L R R L , L L R R R L 
   
  CAVES
  Bandit cave - L R 
  North Mine - R L L L 
  South Mine - R L L R L R 
  Marcos - L R 
  Olav - L L R R 
   
  OTHER
  Pass - R L R 
  Ice Dragon - L R 
  Stone Dragon - L R R L R L L R , L R L 
  Tower near swamps - R L L 
  Cavalorn’s Hut - L R R 
  Talbin (from left) - L R R L , R R L R L 
  Old Xardas Tower - R L L R 
  Sunk Xardas Tower - L L R R L L R 
   
 * * * * *  * * *
   ~~JARKENDAR~~
  
  PIRATES
  Jack Aligator- R L 
  Skip - R L R R 
  Greg - L R R L L L 
  
  SWAMPS
  (from right) - R L L R 
  Secret pass connecting canyon and swamps (from right) - L R R L R , L R R L R , L L R R R L , R L R R L R 
  Juan - L L 
  Over the ladder - R R L R R L 
  Inn, closed room - R R L R R R , L L L R R L L R 
  Estaban - L R R L R L L R L , L L L L R L 
  Houses of dead slaves - 6xR 
  Temple - R L L R R L L 
  Mine (from right) - R L R R L L R L , L R R L R 
   
  CAVES
  Cave on the way to pirates’ camp (from left) - L R R L L L , L L R R R L 
  Cave in the Canyon - R L L R R L 
  Cavity in the rock - R R L L , L R R L R 
  Cave of goblins - L L L R R R 
   
  OTHER
  Bandits' tower - L L R R 
  Orcs’ tent in Canyon - L R R L L L 
  Ruins in Canyon - R R L R L R L 
  Ruins near Eremita’s hut - L R , L R L R L L L 
  Ruins on the south (from left) - L R L L , R L , second ruins: R R L R R R L L