So! Interesting things about nanolaminate armour.
The best 'test' of it undoubtedly comes in 'Gravity of Wishes' when a Graze Ritter is (unwillingly) put through the effects of re-entry. It's important to note that Mika kills the pilot before using the Graze as a heat-shield. We therefore lack information on whether the friction heat would have killed him, had he gone in alive. Given heat definitely transfers into the cabin in other cases, I wouldn't bet against it.
As you can see from this sequence, the Graze appears generally intact but has suffered structural stress on the way down. As Tekkadan realises Mika has survived, the Graze's rear skirt breaks off entirely.
Again, with the pilot dead, it's not super clear whether the 'suit is functional in this state. Very clearly, though, you don't want to raw dog re-entry in an IBO mecha. The armour provides some protection and the individual plates come through in one piece. That's not the same as making the whole machine invulnerable to something traditionally implied to be certain-death in Gundam shows.
Which we of course see reflected when the armour performs it's intended purpose. Because, yes, Ride's Shidan is -- without even the help of its shield -- able to disperse the effects of a full-power beam-weapon (contextually, not good).
However, the magazine on his exposed rifle detonates with the heat, destroying the hand that was holding it.
And the whole machine is left smoking and disrupted by the intensity of the attack.
Even for a mobile suit equipped with nanolaminate armour (which is canonically strengthened by the flow of Ahab particles from the 'suit's reactor), a head-on beam-weapon blast isn't something to be taken lightly. Part of this does appear to be how prepared the pilot is for the effect. Ride charges in without knowing what he's facing. In the next episode, however, Chad is able to weather the attack much more easily simply by knowing that it's coming.
If it's not clear from the screengrab, he's using his Landman Rodi's arm to shield the main torso, rather than unintentionally blocking with his chest. Mika will later deflect another beam in the same fashion.
Something that we do not see is how well the armour holds up to multiple beam-weapon strikes. All the instances covered in the show see a 'suit resisting a single attack, or only tank one out of several (the apparent charging time of the beam is a factor here; Mika deflects Hashmal's aim when he arrives for the final confrontation, sending the blast into the sky, and it's a short while before the mobile armour fires the above shot). This is potentially significant since we know the nanolaminate is a coating on the armour, not an inherent property of the components themselves. There's such a thing as nanolaminate paint, and we know it can wear out (see McGillis' slightly confusing comments vis a vis Barbatos' thrusters in 'Beyond the Red Sky').
It might therefore be possible for repeated beam-weapon attacks to overwhelm a mobile suit's defences. This may be a factor in the re-entry problem too, where even this miraculous protection would be worn away by the sustained heat.
Additional evidence for the limits of nanolaminate comes in the form of Biscuit mentioning 'anti-ship napalm' as a close-range weapon for space combat. If we assume this shares qualities with regular napalm, then it would be a sticky substance delivering high heat to an affected surface. Ideal, perhaps, for burning away the nanolaminate coating protecting a spaceship's hull.
The picture that emerges from all this is of a coating easily capable of handling glancing blows from high-intensity beam-weaponry but that might rapidly degrade under repeated impacts, multiple angles of attack, or a sustained assault. This would still allow IBO 'suits to weather the 'average' beam-weaponry from other Gundam series, but wouldn't completely neutralise the higher-output models such as the Wing Zero's Buster Rifles or, crucially, beam-sabers. You're not immediately cutting off limbs with one of those, but if you're able to stab a beam-saber right up against a piece of nanolaminated armour, it's plausible you'd nevertheless be able to melt through it.
Where this leaves us in terms of overall 'strength' or 'power' when comparing mobile suits from across the franchise, I don't know. It's not like 'can easily weather glancing blows from beam-weaponry' isn't utterly game-breaking in the wider context. However . . . well, I already mentioned the Buster Rifles and those are far from the only beam-weapons that are comparable to or higher-output than the mobile armour beam-weapons in IBO. With the best will in the world, I doubt any IBO 'suit is surviving, say, a direct blast from the Solar System or a Colony Laser, something that taxed even the Unicorns . . .
