Given a simple graph 𝒜 = (V𝒜, E𝒜). The Euler-Sombor index of 𝒜 is given by  EU(𝒜) = Stk∈E𝒜 √h(t)2 + h(k)2 + h(t)h(k), in which η(c) is the degree of c ∈ V𝒜. In this paper, we focus on the chemical graphs which are simple graphs with property η(τ) ≤ 4 for any vertex τ ∈ V𝒜. We investigate the extremal problems of the EU index on the chemical graphs and find the sharp bounds for this index. Furthermore, we obtain the Euler-Sombor index for some nanostructures including Octagonal tilling OT[p, q], HAC5 C6 C7 [p,q] nanotube, titania TiO2 [p, q] nanotube, and nanosheet VC5 C7 [p, q].