There are claims that Nebuchadnezzar himself wrote a whole chapter of the Bible (Daniel 4). I am not aware of any OT Scripture that is considered inspired from God when God didn't speak through a prophet, as Hosea 12:10, Hebrews 1:1, 2 Peter 3:2 teaches. To my understanding of how Scripture comes about, Daniel 4 is the accounting of what took place spoken by the Holy Spirit to Daniel. Am I wrong?
You are not wrong. God controlled the content of the Bible by inspiring prophets and apostles to write exactly what he wanted written down. Daniel wrote the words of his book. That includes the content of chapter four.
In addition to the Scripture references you passed along, we could also add 2 Timothy 3:16 and 2 Peter 1:20-21.