My own research into this came up with the following:
Ranked by their nutrient density.the varieties listed here contain the most protein, fiber, B-vitamins, calcium, minerals, and vitamin E for the least amount of saturated fat: 1.Almonds 2. Filberts (hazelnuts) 3. Peanuts 4. Chestnuts 5. Pistachios 6. Walnuts 7.Cashews 8. Pecans 9. Macadamias
Nutrients in one ounce of almonds (a medium-size handful):
• 166 calories
• 5 grams of protein
• 14 grams of fat (90 percent unsaturated)
• 4 grams of fiber (the highest fiber content of any nut or
• 80 milligrams of calcium
• 1.4 milligrams of zinc
• 1 milligram of iron
• 6.7 milligrams of vitamin E
• some B-vitamins, minerals, and selenium
Though ranked the best, I Iearned from a practioner of Ayurvedic medicine that almonds are not easily digestible - so that's something to consider also
Filberts, (hazelnuts) because they are high in the amino acid tryptophan, are a good nut for sleep. Almonds and filberts have the most vitamin E (6.7 milligrams per ounce) - nearly 25 percent of the adult recommended dietary allowance.
Walnuts have the greatest concentration of omega-3 fatty acids.
Chestnuts are lowest in fat, containing only about 10 percent as much fat as other nuts. What little fat is in the chestnut (1.3 grams per ounce) is nearly all the unsaturated type. Chestnuts also contain three grams of fiber per ounce, but they are relatively low in protein.
It is interesting to note that soybean nuts and peanuts which are not really nuts at all.but legumes meaning that they come from plants rather than trees, are very nutritious. Soybean nuts, while less popular because of their less appealing taste, are actually the most nutritious nut.
I hope this helpful
There are some excellent sites to consult on nut nutrition..I Iiked this one - it was the most informative: AskDrSears.com