with rws as (
  select '{"List":["Steven","Nancy"]}' names from dual
) 
  select *
  from   rws, json_table (
    names, '$' columns (
      nested path '$.List[*]' columns (
        nm path '$'
      )
    )
  ) j;

NAMES                         NM       
{"List":["Steven","Nancy"]}   Steven   
{"List":["Steven","Nancy"]}   Nancy 

with rws as (
  select '{"List":["Steven","Nancy"]}' names from dual
) 
  select j.nm, e.employee_id
  from   rws, json_table (
    names, '$' columns (
      nested path '$.List[*]' columns (
        nm path '$'
      )
    )
  ) j
  join   hr.employees e
  on     e.first_name = j.nm;

NM       EMPLOYEE_ID   
Steven             100 
Steven             128 
Nancy              108