Nozick against the idea that people can have positive rights

Nozick rejects Rawlsian redistributive schemes, arguing as follows:

The major objection to speaking of everyones having a right to various things such as equality of opportunity, life, and so on, and enforcing this right, is that these rights require a substructure of things and materials and actions; and other people may have rights and entitlements over those.  No one has a right to something whose realization requires certain uses of things and activities that other people have rights and entitlements over. (Nozick, Anarchy, State and Utopia, p. 238)

Evaluate this specific argument from Nozick against the idea that people can have positive rights (e.g., a right to equality of opportunity, shelter, health care, etc.) and that society can enforce this right.