Hi Tanya,
Contouring is the best trick to making a big nose appear smaller. To contour is to create shadows that help to sculpt the face where needed. Apply two lines of a darker foundation along the outer length of the nose at the width that you would like your nose to be. Blend very well. If your nose is too long apply the same darker shade foundation to the end of your nose to create the shortening illusion. Be very subtle and light handed. Again blend well. You will notice that your nose is narrower and shorter. But to complete this effect apply a lighter shade of foundation or your concealer down the middle of your nose starting between the brows. Lightly dust a small amount of transclucent powder over the nose to set the foundation.