Yes, you can do that as if it was a page, basically. In the blog, you click on the three dots on top in the Conflence menu and click “Move”. You will then see a dialog in which you can choose the space you want the blog to live in.
Please note: You’ll need the ‘Delete blog’ permission in the current space, and ‘Add blog’ permission in the new (destination) space to do this.
Here the detailed info in the Atlassian documentation: https://confluence.atlassian.com/doc/blog-posts-834222533.html