SELECT 
       'HAB' AS NAME,
       CASE 
           WHEN REGEXP_LIKE(LIST_TXT, '(^|,)201(,|$)') THEN 'YES' 
       END AS MC_NM
  FROM TABLE1
)
SELECT * FROM HAB;

my reg expression works as expected outside of Snowflake, but it gives me null for MC_NM even though there is LIST_TXT with 201 in it.