According to the updated FAQ on the MGSV site, there are plans for official tournaments for Metal Gear Online. These will be announced in the future.

Ushering in a new era for the METAL GEAR franchise with cutting-edge technology powered by the Fox Engine, METAL GEAR SOLID V: The Phantom Pain, will provide players a first-rate gaming experience as they are offered tactical freedom to carry out open-world missions. Metal Gear Online, however, is different. This time Konami isn’t pushing MGO as a secondary component to a single-player game, but as the starter pack for a separate, evolving online action game. Metal Gear Online 3 is the online multiplayer component of Metal Gear Solid 5: The Phantom Pain. IGN's wiki guide will keep you up to date with every secret and tip you need to know to prosper.

MGO Teaser Site

The FAQ also confirms that Metal Gear Online will allow you to play with players from all over the world. Earlier, the team said that there are plans to make the game region free, and now it seems to be official. The Japanese FAQ mentions that players will be able to choose between ‘Japan’ and “ROW’ (rest of world), but this isn’t explicitly stated in the English FAQ so perhaps the menu will work a bit differently.

Metal Gear Online Mgsv

Source: MGSV FAQ, via MGOForums