My favorite is essentially the same as Sarbar.

One serving of Minute Rice (there are several that will work), one packet of Cream of Mushroom Cup-a-Soup, some freeze-dried peas (not the supermarket dried ones -- unless you want to soak them all day in your water bottle) and a 3-oz pouch of tuna (there's more nutrition in the oil packed ones). Sometimes I dust the top with crushed crackers and maybe a little of the shelf-stable powdered cheese (your choice of flavor). This works well with olive oil, protein powder and/or nuts for added nutrition. Also, a small handful of the oriental dried mushrooms weighs nothing, adds no nutrition, but tastes glorious.

Incidentally, like others here, I'm not really a big fan of instant rice, so if I have time and fuel, I'll take just plain ordinary white rice. If you will bring it to a boil in broth, and boil rapidly for just one minute, you can put the pot aside and the rice will be fully cooked in just a few minutes (never actually timed it, just checked to see when all the broth is absorbed). I don't have any explanation for why this works, but I sometimes use this method at home as well.

Another recipe I like is Spanish rice. Half a cup of Minute rice, two tbls of freeze-dried pepper flakes, a pkg of tomato
Cup-a-Soup, one tbls of bacon bits, one Slim Jim sliced thin, one tbls of freeze-dried onion flakes, salt and pepper (go easy) one tbls of chilli powder, and one of protien powder. This is good with added cashews and/or olive oil for even more nutrition, and for more bulk, just increase the rice.

Best, jcp