Everton have made no secret of their interest in the Icelandic midfielder as they look to continue an impressive summer transfer window haul which has already seen the arrival of six players, most recently of all, Wayne Rooney.
However, a potential stumbling block was formed when the Welsh side reportedly demanded a staggering £50m (€56.65m) with former Premier League champions Leicester City also interested in his signature.
Despite the asking price being extremely inflated, Nevin believes the 27-year-old could be a great signing and could easily pay back the huge sum.
"I think he's a fabulous player... £40-50m, yes it's a stupid amount of money," the former Scotland international said, as quoted on BBC.
"But if he goes and gets you into the Champions League, well that will not seem like a daft amount of money."
Sigurdsson is believed to be a major reason why Swansea City stayed up in the Premier League last season thanks to his nine goals and 13 assists.
Few players can make such a difference on their own which is why Nevin believes the Toffees should continue to pursue the former Tottenham Hotspur player.
"There's a few of us out there that think this guy's extra special and can give you that one thing, that one piece of class that you need to make yourself different from the rest," he added.
"Sigurdsson gets a game wherever he goes and looks perfectly good in any team you put him in, he's a fabulous player and I think he single-handedly kept his club up last season."