Maybe its possible to do it the other way around; first the nitro group and then the CH3.
Nitrate benzene, or start with nitrobenzene an m-director.
Then use methane iodide and a catalyst. Thing is you can't use a smaller halogen then I. Because smaller methylhalogens have a BP below room temperature and are very carcinogenic (not a fun combination
). And does CH3I with AlCl3 or another catalyst work?
If not then reaction with HCOCl + AlCl3, or para-formaldehyde, followed by a reduction might work. Although reaction with para-formaldehyde can (as I have once synthesized after discovering it as a by-product of a chloromethylation reaction) also give a bis-aromatic product Ar/\O/\O/\Ar.
PS: This hole post might be nonsense, but I am just wondering whether a shorter reaction route is possible.
Also if you were to synthesize a bigger alkyl group than methyl, the nitro group first method would definetely be easier and arguably better than starting from the alkyl-aromatic.
Another point I would like to make with this post is that in synthesis problems creativity is of crucial importance.