There's no such thing as a "wheat nickel", only wheat-back cents. A 1906 nickel would be a Liberty Head nickel, with a picture of Miss Liberty on the front and a large V (the Roman numeral for 5) on the back.
what does a 1857 nickel look like
The value of the 1906 V nickel varies greatly depending on the condition of the coin. This nickel can be worth as much as about 4 dollars depending on its definition.
There is no such thing as a 1906 Indian head nickel(*). The first nickel with that design was issued in 1913. The previous design is called a Liberty nickel; you can find a list of prices at the attached link.
Please check your coin again and post a new question. Buffalo nickels were made from 1913 to 1938, and were never struck in silver. A 1906 nickel would be called a Liberty Head nickel, and like all nickels except the famous "war nickels" of 1942-45, it's made of an alloy of copper and nickel, hence the name "nickel".
1906 is a common date for Liberty Head nickels, most circulated coins are valued at $1.00-$3.00
The only silver nickels ever made were made in 1942-1945. These nickels contain 35% silver. So a 1906 US silver nickel is worth nothing because there is nothing like that. See the related question below for the value of a 1906 US nickel.
It's a Liberty Head Nickel the date 1906 is very common, values are at $2.00-$5.00 for average coins
In good condition about $2.00
Must be appraised by a professional.
Additional information is necessary to properly value your rifle. There were two models available in the Winchester Model 1906. One had a straight stock and the other had a pistol grip stock and was called a Model 1906 Expert. Which one do you have? Also, you did not say, if your rifle was partially trimmed in nickel or was fully nickel trimmed?
A US one cent coin dated 1906 is a Indian Head (1859-1909) cent.
In average condition, it's worth about a dollar.