Answer: Yes.
Explanation: Fascism is an EXTREME form of nationalism. Also, fascism isn't just being nationalist. A fascist system requires authoritarianism, militarism and the belief in a natural social hierarchy. Being nationalist is identifying with and supporting one's nation, and placing the needs of one's own nation over the needs of others.
It is also worth noting that many believe that fascism requires an idea of racial supremacy, something we saw in both Italy and Germany during the second world war and the years prior.