You are right, the second farm would produce beef which emit a lot more co2. However, even with the best practices the beef stay way more polluting than any other food as their emissions do not go below 40kg/co2 per kg of meat. This is due to the fact that a big part of the emissions are due to methane emitted by cows.

I guess that it depend on both of the kind of nuts and where they grow. I’ve heard that Californian almonds require a lot of water, but they grow on the wild on the south of France (so without any irrigation).