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.