Yes! Unless the publisher has explicitly stated they do not want YouTuber's monetizing off of their games, you are able to upload and monetize that content. That being said, you should make sure that you include additional original content so that your productions can be considered as fair use, such as by adding commentary related to the game that you are playing.
Keep in mind, most publishers only allow monetization of their game and not of any of the music they have licensed from third-party. Be mindful for any in-game radios or songs that are not covered under their license.
Check out George's video below for additional details:
To learn more about the monetization of video game and software content, click here.
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