If your domestic helper is from the Pakistan I'm afraid you are probably out of luck (there is no "nanny" classification with the MOM as it is considered to fall under the heading of FDW (Foreign Domestic Worker) As such, Pakistan is not considered as a source country by the MOM. Construction Labourers, yes, but FDW's no.
If you bring her in on a Social Visit Pass, she is almost sure to get caught. If that happens both she and you might find yourselves on planes back to Pakistan so I don't advise trying it.
https://www.mom.gov.sg/passes-and-permi ... ligibility
Foreign domestic worker eligibility
A foreign domestic worker (FDW) needs to meet age, nationality and education requirements to get a Work Permit.
Who is eligible
The foreign domestic worker you hire needs to meet these requirements:
Gender - Female.
Age - From 23 to below 50 years old at the time of application. FDWs aged 50 and above can only renew their work permits until they reach 60 years old.
Source country or region - From an approved source country or region, including Bangladesh, Cambodia, Hong Kong, India, Indonesia, Macau, Malaysia, Myanmar, Philippines, South Korea, Sri Lanka, Taiwan, Thailand.
Education - Minimum 8 years of formal education with a recognised certificate.
https://www.mom.gov.sg/~/media/mom/docu ... .pdf?la=en