can you teach me how to draw portaits like that because it's so well done
I don't personally teach about pixel art but i can give you some pointers.
The NT style has big thick outlines and lots of anti-aliasing, if you're not experienced in actual pixel art then a great starting point would be "Pixel logic" by Michafrar https://gumroad.com/l/pixel-logic .
Or if you want a free guide check out this pixel joint forum thread http://pixeljoint.com/forum/forum_posts.asp?TID=11299 .
Saint11 also has a great collection of tutorials https://blog.studiominiboss.com/pixelart . Good luck!