Europe's contemporary political landscape has been shaped by massive shifts in recent decades caused by geopolitical upheavals such as Brexit and now, COVID-19. The way in which policy makers respond to the current pandemic could have large effects on how the world looks after the pandemic subsides. We aim to investigate complex questions post COVID-19 around the relationships and intersections concerning nationalism, religiosity, and anti-immigrant sentiment from a socio-cognitive perspective by applying a mixed-method approach (survey and modelling); in a context where unprecedented contagion threats have caused huge instability. There are still significant gaps in the scholarly literature on populism and nationalism. In particular, there is a lack of attention to the role of evolved human psychology in responding to persistent threats, which can fall into four broad categories in the literature: predation (threats to one's life via being eaten or killed in some other way), contagion (threats to one's life via physical infection), natural (threats to one's life via natural disasters), and social (threats to one's life by destroying social standing). These threats have been discussed in light of their effects on religion and other forms of behaviour, but they have not been employed to study nationalist and populist behaviours. In what follows, two studies are presented that begin to fill this gap in the literature. The first is a survey used to inform our theoretical framework and explore the different possible relationships in an online sample. The second is a study of a computer simulation. Both studies (completed in 2020) found very clear effects among the relevant variables, enabling us to identify trends that require further explanation and research as we move toward models that can adequately inform policy discussions.