You can use your Ninja blender as a food chopper.
I use my Ninja blender as a food chopper and it works fine although a dedicated food processor or food chopper works better.
A Ninja blender can handle basic chopping of foods, especially when you use the pulse function for controlled processing.
Many Ninja blenders also have a pulse function, which allows you do short bursts of blending which is also ideal for chopping of foods and prevents over processing of the foods and also helps to achieve a desired consistency.
Ninja blenders are also made and designed with blades which can also effectively chop ingredients, especially when it's used with the pulse function on your Ninja blender or for other tasks such as making of sauces or smoothies.
Even certain types of Ninja blender models like the Ninja Foodi Power Blender & Processor System are also designed specifically with food processing capabilities, which include chopping of foods.
These models of Ninja Blenders also often come with additional types of attachments and programs which offer more options for food processing.
Ninja blenders are suitable for simple chopping tasks like chopping of vegetables such as peppers, onions and some fruits and they can also effectively blend ingredients for sauces, pesto and dips and even make smoothies and purees.
Ninja blenders are great at creating smooth and consistent textures for soups, purees and smoothies.
Although food processors are best for shredding cheese, slicing of vegetables and kneading of dough due to their specialized blades and wider bowls.
And for larger quantities of food or when you need precise textures such as making of pastry dough then a food processor is best.