I'm always wary of saying "this word means this good thing", and "that word means this bad thing", when in fact both words have been, and often still are, used in different ways than that. Certainly, when people use the word "patriotism", they are often referring to something more akin to how you've described "nationalism".

That said, I do think that there are healthy ways to feel pride or love for your country, and unhealthy ways to feel pride or love for your country. And I do think your distinction between pride or love that is unconditional vs that which is clear-headed, appraising, sometimes critical, and always improvement-seeking, is a good heuristic for distinguishing between the bad kind from the good kind.