Can I only eat it in Chiang Mai?
No. It is a signature dish eaten in many northern cities. If you are meeting northern food for the first time in Chiang Mai, a bowl of khao soi is a good place to start.
Khao Soi · ข้าวซอย
If you are choosing a meal in Chiang Mai, try khao soi. Egg noodles sit in a coconut curry broth, topped with noodles fried until crisp, and it is a signature dish of the north. There is fun in alternating soft noodles and crispy noodles. If lime comes on the side, taste the broth first, then squeeze in a little.

A rich curry broth and two kinds of noodle define it. The topping noodles are crisp at first and soften little by little as they touch the broth. Taste the broth before and after you add the side dishes, and you get different flavours in one bowl.
Try the crispy noodles on top before they get soaked in the broth.
Khao soi is well known on trips to Chiang Mai, but it is eaten in other northern cities too. Unlike a northern meal laid out with sticky rice and side dishes, it puts noodles and broth in one bowl. It is also a good choice when you are eating alone or want a light lunch.
No. It is a signature dish eaten in many northern cities. If you are meeting northern food for the first time in Chiang Mai, a bowl of khao soi is a good place to start.
There are menus with chicken, beef and others. Look at the main ingredient written on the menu and choose what you want. Not every shop uses the same meat.
If you would like to read more about the food and the regions behind it, these sources are worth a look. Ingredients and cooking methods can vary from one cook to the next.
Sharing image credit: Takeaway · CC BY-SA 3.0