Well, an "opportunity" is not the same as a "chance", Bamboo. It could be "sort of" construed the same way but "opportunity" conveys more that the immigrant sees the possibilities and can act on them. "Chance" conveys randomness which isn't really what this sentence means.The United States is viewed as a land of golden opportunity by many immigrants.
Is it proper to look at "a land of golden opportunity" as "a country full of wonderful chances?" Thanks.