Yes, this is The Nibelungenlied (in D.G. Mowatt's prose translation), the source material for Wagner's 4-opera, 14-hour Der Ring des Nibelungen cycle. I, like most folks, have been exposed to snippets of this over the years but have not sat through even one of the operas complete, let alone the entire cycle (various versions of which are available on DVD from Amazon). As such, I was generally familiar with some of the characters, and a few bits of the action, but at a sufficient distance that most of this was "fresh" in reading.
I had planned to have knocked down this back-to-back with Beowulf, as this was penned in Middle High German a few centuries past that, but likewise looking back towards a semi-mythical time around the fifth century. I don't know if it is the source material or the translation, but The Nibelungenlied was a far more "accessible" read in that it is much easier to follow the characters and action in this.
However, I kept finding myself thinking of less-than-flattering modern parallels to what was happening in the book. The first third or so was pretty much "soap opera with some fantastic elements", sort of like Dark Shadows but without the vampires, the second third or so was a lot like the Rambo movies, with a few key warriors killing hundreds if not thousands of enemies without incurring much damage themselves, and a finish that was, so bloody that it brought to mind the classic Monty Python Sam Peckinpah's "Salad Days" sketch. All of this set in a context of "courtly" behavior and exchanged obligations that, by the end, make the web of alliances that got the first World War started seem rational (frankly, one of the "best parts" in this is the long exchange between Rüdeger and the Burgundians in which both sides are anguishing over not wanting to fight each other, which greatly echoes Arjuna's angst at Kurukshetra, making me wonder if the much older Indian epic, Mahabharata had somehow managed to influence this story).
While the characters of The Nibelungenlied are familiar to modern folks via Wagner's works, it was surprising how little of the Germanic/Norse mythology appears in this. While there are Dwarfs, Giants, magic cloaks of invisibility, Dragons, etc., etc., etc., there are no appearances of Wotan, Valhalla, Yggdrasil, the Norns (although an analogous, if minor, scene is in this), Valkyries, etc., and a central character to this story, Kriemhilde (sister to Gunther, wife, and eventual avenger, of Sifrid) is left out of the operas!
One thing I found interesting was how wide-spread (for the 5th century) the locations were ... there were folks from Iceland, Denmark, Burgundy, Verona, Hungary, the Netherlands, and mentions of others ... quite the "international" slate of characters for the age. Anyway, sound like fun? It's just $3.50 in the Dover Thrift Edition (this is the last of that recent bunch that I'd ordered), so you're not likely to do better than picking that up at cover price.