It's been on the rise for a while now. It's been on the rise with UKIP in the UK, the FN in France, Golden Dawn in Greece and others elsewhere.
It's an inevitable reaction to global financial turmoil stemming back to 2008, so yes it can certainly be eliminated by improving the health of the world economy, but I don't think that in itself justifies giving Greece a free ride because the implications of giving Greece a free ride could in themselves cause more problems elsewhere.
Greece has long been a hot bed of far right and far left nationalism- from various terrorist groups, through to a disturbing amount of Greeks that went to help commit atrocities in former Yugoslavia including the Srebrenica massacre. As awful as it may sound, it is perhaps better to simply let Greece return to it's status quo and contain it and let everyone else ditch the nationalist sentiment than it would be to give Greece a free ride and give cause for nationalism to take hold through the rest of Europe.
There are also cases, as with Russia, whereby we tried to help bring them aboard the global economic boom over the last 15 years, but whereby all it meant was they got stronger and used that strength to drive their far right nationalism through their neighbour's backyard. It seems preferable therefore that Russia is poor and far-right nationalist, than wealthy and far-right nationalist. In some cases like with Russia, you couldn't win either way if you wanted to when the majority of the population are fundamentally just far right in their views.
So yes the rise of nationalism concerns me, but I don't think we can assume we can rid ourselves of it any time soon. I think the best option is to eliminate it where we can, and contain the rest of it. There are promising signs - in the UK for example Scottish nationalist ambitions were thankfully struck down in a referendum that was even slanted towards the nationalist view and UKIP underperformed at the general election.