回复：投资120万美元 保证全家立刻拿到美国PR 可能吗？

yes.
you can just invest 1 million or less and provide several jobs and get PR for your family. not "立刻". take about 1 year or more time to get conditional PR. then 2 year later get PR. so it is about 3 years.

投资 immigration PR

"名额有限。。。" each country do have quota for almost any kind PR each year. but 投资 immigration PR quota is not as tight as other kind PR.

as any kind investment, if you not careful, you may lost some of your investment and may not get your PR if the venture unsucessful at end of 3 years. (Not "保证")