U can start giving nuts after 8 or 10 months... Start very slowly by giving a pinch per day... Start with badham, cashew and then peanut... Beware of peanut allergy as well.. but in India we don't see much of peanut allergy For babies more than one year with no nuts allergy def we can give nuts for weight gain... Dry roast and grind all nuts(badam, pistachio, cashew) and add a small spoon full in any poridge, kheer etc... You can also try dry fruits