A typical 1 oz serving of roasted chestnuts contains 0.9 grams of protein (3.17 g per 100 g), which makes it only a minor source of protein. That covers roughly 2% of the 50 g reference Daily Value, so it adds toward your protein total for the day.
Only about 5% of the calories in roasted chestnuts come from protein, so it is more of an energy food than a protein food. It is worth eating for other reasons; the protein it adds to a day is incidental.
Among the 31 nuts in the database, roasted chestnuts ranks 30th by protein per serving, and 738th out of all 796 foods on the site. Set against beechnuts, another nut entry in the database, a serving carries about 0.8 g less protein (beechnuts has 1.7 g per 1 oz).
It is an incomplete protein on its own; pairing it with other plant foods across the day covers the full range of essential amino acids. The serving above is measured by weight at 28 g. The per-100 g figure lets you compare it directly against any other food here, whatever its serving.
Chestnuts are mostly starch, which makes them far lower in protein and fat than other nuts.
Source: USDA FoodData Central #170190 - "Nuts, chestnuts, european, roasted" (SR Legacy, published 4/1/2019). Values are the published reference figures for that record, not lab measurements for a specific brand or batch.
Quick answers
Roasted chestnuts protein FAQ
How much protein is in roasted chestnuts per 100 g?
Roasted chestnuts has 3.17 g of protein per 100 g. A typical 1 oz serving (28 g) provides 0.9 g.
Is roasted chestnuts a complete protein?
No. Roasted chestnuts is an incomplete protein on its own; pairing it with other protein sources across the day covers the full range of essential amino acids.
How much of the Daily Value does a serving of roasted chestnuts cover?
A 1 oz serving of roasted chestnuts contains 0.9 g of protein, about 2% of the 50 g reference Daily Value.
Is roasted chestnuts a good source of protein?
Roasted chestnuts is only a minor source of protein, and about 5% of its calories come from protein, which makes it more of an energy food than a protein food. Set against beechnuts, another nut entry in the database, a serving carries about 0.8 g less protein (beechnuts has 1.7 g per 1 oz).