Protein and amino acids
Eggs are a benchmark complete protein: a large egg carries about 6 to 7 g of protein containing all nine essential amino acids in a highly digestible form. That is why eggs are a reference food in nutrition science.
Calories and fat
A large egg is roughly 70 to 78 calories, with the fat (and most micronutrients) in the yolk and the protein split between white and yolk. The exact figure scales with weight grade, from Small to Jumbo.
Vitamins, minerals and shell colour
Eggs supply vitamin B12, vitamin D, choline and selenium among others. Shell colour comes from the hen breed, not nutrition, so white and brown eggs are essentially identical inside. See white vs brown table eggs.