Could you give me both lists (both successful and unsuccessful nation building)?
Successful: Japan, S. Korea, Germany, Grenada, Panama
Unsuccessful: Iraq, Afghanistan, maybe a lot of S./Central America depending on how you define nation building, Vietnam, Cambodia (sort of)
Trade with the US represents not quite 1/4 of the Vietnamese economy. $46b in imports from Vietnam last year, with their GDP being near $200b. That's a 10x increase in imports from Vietnam since 2003 (their economy has increased in size by about 5x in that time, non-inflation adjusted). In the coming two decades, trade with the US will probably turn Vietnam into one of the world's 25 largest economies.
The US appears to be intentionally trying to build up Vietnam to help offset the rising hegemony of China in the region. We're running a vast trade deficit with them (5 to 1 ratio), and hardly a word is being said about it. The recent military interactions bolster that notion.
Colombia is an example of successful nation building (more like guiding/assisting, frankly) in South America. Certainly if we're listing failures in S.America, that's one of the successes. Their GDP increased from $40b in 1990, to $380b by 2013. It's a dramatically improved nation compared to 30 years ago, in just about all regards. The US has been aggressively intertwined (some would say too much) with Colombia the whole way.
But look what the US left behind when it withdrew from those nations. Independent, stable, wealthy, democratic, growing, peaceful countries which now rank high on most development indices.
Nation-building is the best term in these two cases, regardless of the circumstances of "entry"