Peachface are the easiest of all the lovebirds to breed so naturally almost anything will satisfy a nesting hen. The mostly commonly used nesting materials are wood shavings, newspaper, Carefresh & straw or hay. Depending on the area you are in palm fronds & other leafy materials will do well. Peachface don't build fancy nests like the eyering species, but some hens do build nice nests. If you do decide to use wood shavings please be sure they are bird safe. Many websites list the various woods that are bird safe. Let safety be your guide -- if you don't know, don't use it.
The paper is the easiest of the products to come by -- it makes a great outlet for junk mail, old newspaper, extra printer paper -- just be sure that their isn't a lot of printing as the hen will chew the paper and no one really likes the taste of ink. Carefresh & wood shavings can be found in most pet sections of the stores. If your local grocery store doesn't carry those products, try a pet speciality store. Lastly, the palm fronds can be purchased in the home & garden section of a department store or at the local nursery. Be sure to check that the plants have not been treated with any pesticides as these are toxic to your birds!