Hmmmm. I can't see Indonesia taking over the Philipines, not without a really bizarre POD way back.
I could see Indonesia prosecuting a Malaysian War, or going for the whole of New Guineau, if conditions were right. Malaysia easier, paradoxically than New Guineau. I could see, for instance, circumstances where Indonesia intervened in/covertly managed a Bornean Malaysian indepence campaign... much the way East Pakistan broke into Bangladesh. Or situations where collapse or weakness of the Malaysian government lead to an opportunistic invasion and occupation, with the west just standing back for some reason.
I have more difficulty seeing a takeover of Papua New Guineau, for no other reason that the Australians would have conniptions and would do their utmost to drag Britain and the United States in.
The trouble with the Phillipines is that America's invested heavily in Subic Bay and Clark Air Force. And the Phillipines was the major platform for American operations in Vietnam, and for support in South Korea, Taiwan and Japan. Go at the Phillipines, you might as well declare war on the US.
On the other hand, the Moro Islands were majority muslim and home to a substantial independence movement. I could see Indonesia pursuing designs there, and maybe feeding the Moro movement.
Beyond that, I can't imagine a situation of disintegration of the Phillipine polity and American abandonment that would allow such a thing.
Still, if you'd like... go for it, could be a fun timeline. And there's not enough Indonesian Timelines.