"nachash", dragon or snake in Scripture?

I think I remember Dr. Scott Hahn saying that the Hebrew (?) word “nachash” can be translated as “dragon” as opposed to, or perhaps in addition to, serpent.
Can anyone help me nail this down? Sources, etc?
I’ve found a couple of places that say dragon and serpent are interchanged rather liberally in Scripture, but I’d like more than that to make my point in a discussion.

From the St. Paul Center Bible study “Genesis to Jesus”

b. That Snake Adam Saw

Let’s back up a few paces. Let’s look at our characters. First, who’s this “serpent”?

We’re all used to the storybook Bible image of the long, thin snake slithering around the apple tree. But we might have to change our visual image of this scene.

The Hebrew word used to describe the “serpent,” nahash, implies something much more deadly.

Throughout the Old Testament nahash is used to refer to powerful, even gigantic, evil creatures. Isaiah calls the nahash a sea dragon, the great Leviathan (see Isaiah 27:1). Job also uses nahash to depict terrible sea monsters (see Job 26:13).

This is clearly the image the Book of Revelation has in mind when it describes “a huge red dragon” in the heavens, “the huge dragon, the ancient serpent, who is called the Devil and Satan, who deceived the whole world” (see Revelation 12:3,9).

The Church, of course, has always interpreted the serpent in Genesis 3 as Satan, the Devil in slithering form (see Catechism, nos. 391-395). So we know, as readers, something that Adam probably didn’t know - that this encounter with the serpent was a test against evil, a battle for the soul of mankind.

But we need to see what Adam saw. Once we appreciate that the serpent was a lot more than a little garden-variety snake, we begin to understand why Adam failed in his duties to “guard” his wife and Eden (see Genesis 2:15).

Ah! I’m spelling it wrong, which explains part of why I couldn’t find any sources.
Many thanks to you for your help!

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