How to use inner join instead of left join on query below in case of d

Question

I work on sql server 2014 I need to use inner join instead of left join
and update Haschemical i case of exist by haschemical or No in case of not exist
on statement below

i need to use inner join instead of left join because data is very big on table
ExtractReports.dbo.FinalComplanceDataDelivery may be 20 million so query take too much time to execute

so How to do that Please ?

update r set r.HasChemical=case when cm.partid is not null then 'HasChemical' else 'No' end
     from ExtractReports.dbo.FinalComplanceDataDelivery r with(nolock)
     left join 
     Parts.ChemicalMaster cm with(nolock) on cm.partid=r.partid