Hello!
Most verbs ending in "ir" follow the common rule. This means that "ir" is removed from the end of the verb and replaced with the correct ending.
Ir rule:
Je -is
Tu -is
Il -it
Nous -issons
Vous -issez
Ils -issent
However, the verb courir is irregular, and follows a different pattern.
Je cours
Tu cours
Il court
Nous courons
Vous courez
Ils courent
For your question, the form of "courir" for the subject "nous" would be: Nous courons.
I hope this helps you!!