This trophy is pretty easy. A Chip-In is where you hit the ball into the hole from outside the green. Official round simply means you're playing Challenge Mode and there aren't any modifiers active (such as no wind, real golf, etc).
The easiest way to get this is to play the first challenge. Hit the ball so that it's just outside of the green (you should have your AW club if you did it right). Carefully aim and adjust to the pin (it helps if your power is just under the indicator so you don't overshoot the flag) and if it sinks, you'll get the trophy. If not, keep trying until you do. This is one of those trophies you'll likely get without trying but will be tough if you do try so only grind for it if you've beaten the game and still don't have it.