I created Shopping campaigns via AdNabu but there are no impressions in them.

There can be multiple reasons for this.

  1. Kindly check your merchant center and see if the products are approved. In case you have new products in the merchant center, kindly run "Sync Shopping Products".
  2. Your initial bid is too low. Kindly increase the bids in all the three campaigns. Refer to this article to know how to push bids.