A 489 No.

What you've described is categorized as One Effect Makes Another Irrelevant (Player's Handbook, page 172) in the list of magical effect stacking limits. Using Shapechange makes Wild Shape irrelevant, and you would not receive any benefit of Natural Spell while Wild Shape has been made irrelevant to your form. The feat's benefits are limited to "while in a wild shape", which does not include while in a Shapechange form.