Martello will be the second person from outside the Swiss company to take the CFO post in less than a decade. Paul Polman, a former Procter & Gamble Co. executive and now head of Unilever, ran Nestle's finances from 2006 until early 2008.

"For a company of too many 'insiders' at senior level positions, this external perspective and experience could prove to be very useful at Nestle," Andrew Wood, an analyst at Sanford C. Bernstein, wrote in a note to investors that was quoted on Bloomberg News.

But unlike Thomas Russo of Garner Russo, Wood holds the view that "Martello does not have a superstar CV," and believes she may have taken a step back from a more senior position within Wal-Mart. While he's not "bowled over" by Martello's appointment, Wood also isn't giving a final judgment on it, he said.

Nestle may be trying to avoid a similar situation to that of former CFO Polman, who many investors had hoped would become CEO, Wood said.