Disclaimer: These rankings are my opinion and my own. Many of the heroes I have near the bottom of my list are played consistently by some of the best players in the game. I am making these rankings to better my knowledge of the game as well as explain Dota 2 to anyone who might be interested.
Chen is an Intelligent ranged hero, that is useful for Supporting, Jungling, and Pushing. Chen has 4 abilities: Penitence, Holy Persuasion, Divine Favor, and Hand of God.
- Penitence is a Unit Target attack that targets Enemy Units and forces the enemy unit to move slower, and for allies to attack it more quickly.
- Holy Persuasion is a Unit Target spell that allows Chen to take control of an enemy of neutral creep. If the persuaded creep's base health is naturally below the health minimum, its base health will be raised to the health minimum. Converted creeps have increased movement speed and bonus damage.
- Divine Favor is a passive skill that provides an aura that grants increased health regeneration and amplifies all health restore by a percentage. Can be cast on allies to teleport them to Chen. If cast on Chen, all units controlled by Chen will be teleported to him. Taking damage will dispel the buff.
- Hand of God is Chen's Ultimate Skill. It heals all allied heroes on the map as well as all units under Chen's control.
Why I think Chen is the 119th best hero: Chen is very hard to control, as you have to micromanage many units at once. Also, Chen is not very helpful when it comes to teamfighting, except for having healing abilities.
Note: This video is 8 years old, and Chen has been updated slightly in this time, including one skill changed. But, it still provides a basic understanding of his capabilities.