In 1974, Howard Chaykin was still flailing and looking for an artistic identity. One of his early stories was drawing Man-Thing in FEAR 10, Oct 1972 Where Conway(story), Chaykin(pencils) and Morrow(inks) did an improved version of Man-Thing's origin.

Among other work of the period by Chaykin were anthology mystery stories for RED CIRCLE SORCERY, some Solomon Kane stories for MARVEL PREMIERE, SAVAGE SWORD OF CONAN and other titles, and a few other offerings for DC's mystery titles.
Although most of Chaykin's work was in a more science fiction or pulp direction (such as his "Iron Wulf" stories in WEIRD WORLDS 8-10, and THE SCORPION for Seaboard/Atlas), I was impressed early on at Chaykin's versatility across multiple genres. So I think he would have been as interesting and promising a choice as any other for SWAMP THING. He'd already proven his ability to do the series, having drawn a significant origin story for Marvel's version of the same character in FEAR 10.