Short answer. It depends. Article 132 does not itself force every employer to build a nursery -- it authorizes the Secretary of Labor and Employment to require one, by regulation, in appropriate cases. Today, the facility that is actually mandated is the lactation station under Republic Act No. 10028, while broader workplace safety standards fall under Republic Act No. 11058.
What the law says
In appropriate cases, he shall, by regulations, require any employer to: Provide seats proper for women and permit them to use such seats when they are free from work and during working hours, provided they can perform their duties in this position without detriment to efficiency; To establish separate toilet rooms and lavatories for men and women and provide at least a dressing room for women; To establish a nursery in a workplace for the benefit of the women employees therein
Labor Code, Article 132 — Facilities For Women Employees. Read the full provision →
What Article 132 actually says
Article 132 does not itself write "every employer must build a nursery" into law. It gives the Secretary of Labor and Employment the power to set safety and health standards for women employees and, in appropriate cases, to require by regulation that employers provide certain facilities -- proper seating, separate toilets and a dressing room, and a nursery in the workplace for the benefit of the women employees. The nursery obligation, as written, is something the Secretary can require through regulation for particular workplaces, not a blanket duty every employer already carries straight from this article alone.
How this article has been overtaken
The facilities Article 132 lists are no longer the whole picture. Republic Act No. 10028, enacted in 2009, now governs lactation stations and lactation breaks specifically, and Republic Act No. 11058, enacted in 2018, governs occupational safety and health standards and their enforcement more broadly. Article 132's text is reproduced above as originally enacted; the mandatory facility a nursing employee can actually point to today is the lactation station required under RA 10028, not the nursery language in the older article.
The facility that is mandatory today
For an employee who is breastfeeding or expressing milk at work, the operative law is RA 10028, which established the requirement for covered establishments to provide a lactation station and reasonable break time to use it. That is the concrete, enforceable version of the general idea Article 132 gestures at with its nursery provision. If your interest in a workplace nursery is really about breastfeeding support, RA 10028 is the law that carries the actual mandate, and it should be the reference point rather than the original Labor Code text.
If your employer has no nursery or lactation station
Because Article 132's nursery requirement was always conditioned on a regulation applying it to your particular workplace, the stronger claim to raise is under RA 10028, since that law's coverage of lactation stations does not depend on a separate, case-by-case DOLE regulation the way Article 132's language does. General workplace safety and health obligations, including facilities for employees, are also enforceable under RA 11058. Raising the specific facility you are missing, and citing the law that actually governs it, gets a clearer answer than relying on the superseded nursery clause alone.