Mismanaging/squandering/embezzling your country’s oil revenues and a steep decline in said oil revenues without a sovereign wealth cushion was what caused this, not nationalizing food distribution or production.
Certainly the nationalizing seems to be part of it. Attacking the people producing said food for "hoarding" just to appease your socialist backers [1] [2], I must say, also seems less than helpful to my admittedly uninitiated brain. They've been at it for a decade.
[1] https://venezuelanalysis.com/news/11478
[2] http://www.nytimes.com/2007/05/17/world/americas/17venezuela...