Answer: Patriotism
Step-by-step explanation:
Nationalism is the belief that the interest of one's nation should be supported above that of other nations because one's nation is superior.
Patriotism on the other hand refers to loving and supporting one's nation but not to the detriment of other nations.
Patriotism fits more with the melting pot metaphor because in loving one's country, one will appreciate that there are many different cultures in it that should be respected because they are citizens of that country as well.
This is in opposition to Nationalism which might push for the wellbeing of one group above others with an instance being the activities of White nationalists.