Hi there,
Re: chilli powder and mustard seed
There is a rule by FDA that says, basically, if the nutrition values for a product are below a value, the producer company does not need to specify them. They can say, "no significant amount" or similar statements.
(reference:
What are insignificant amounts of nutrients?
http://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodLabelingNutrition/FoodLabelingGuide/ucm064904.htm )
In your example foods, for chilli,. McCormick seems to be sort of right, on the site they give only sodium value, and the rest is given as 0 because they were properly considered insignificant. Here is their page.
http://www.mccormick.com/Products/Herbs-and-Spices/Spices-A-to-Z/Chili-Powder.aspx
Regarding mustard seed,
http://www.mccormickgourmet.com/Products/Spices/Mustard-Seed-Yellow.aspx
They seem to have made a slight mistake in their judgement. Mustard seed does contain some calories (15 kcal for 1 tsp, according to food database). McCormick site seems to consider the serving size to be 1/4 tsp, so the corresponding calories would be 4kcals (for 1/4 tsp). They seem to have considered 4kcal as insignificant and according to above FDA regulation, values under 5kcal can be labeled as 0.
I would, personally, only consider amounts less than 1kcal as insignificant. But that is their decision...
Hope this helps.