If all the so-called “blackheads” in your nose are all the same size,then they are not blackheads. If, however, you have a “blackhead” that is bigger than the rest of the other “blackheads” in the nose, then it really is a blackhead and not just another sebaceous filament.
What's the difference, you ask? Your skin is covered in hair (even your face is covered in peach fuzz), and every hair follicle contains said hair and an oil gland that produces oil. Sebaceous filaments reside in the lining of your pores, and their primary function is to channel the flow of oil along that lining into the skin to moisturize it. It's natures natural facial oil :) Once the oil is exposed to oxygen, it oxidzes, and can look like a blackhead.
On the flipside... the buildup of said oil, dead skin cells, impurities, pollution, and bacteria, can clog up the opening and will come together to form a blackhead.
Now take a closer look. Are you seeing Sebaceous Filaments? Or blackheads?